U.S. patent number 11,026,128 [Application Number 16/117,738] was granted by the patent office on 2021-06-01 for mechanism to enable interworking between network slicing and evolved packet core connectivity.
This patent grant is currently assigned to QUALCOMM Incorporated. The grantee listed for this patent is QUALCOMM Incorporated. Invention is credited to Stefano Faccin, Sebastian Speicher, Haris Zisimopoulos.
United States Patent |
11,026,128 |
Faccin , et al. |
June 1, 2021 |
Mechanism to enable interworking between network slicing and
evolved packet core connectivity
Abstract
Aspects of the present disclosure relate to a mechanism to
enable interworking between fifth generation system (5GS) network
slicing and evolved packet core (EPC) connectivity. In an example,
techniques are provided for existing packet data unit (PDU)
sessions that provide connectivity to a network slice from a set of
network slices. Connectivity to the network slice is in response to
a user equipment (UE), that uses network slices, moving between a
5G network and a 4G network. The existing PDU sessions are
connected to a dedicated EPC core network that supports the same
services provided by the network slice.
Inventors: |
Faccin; Stefano (San Ysidro,
CA), Zisimopoulos; Haris (London, GB), Speicher;
Sebastian (Wallisellen, CH) |
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
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Assignee: |
QUALCOMM Incorporated (San
Diego, CA)
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Family
ID: |
1000005592627 |
Appl.
No.: |
16/117,738 |
Filed: |
August 30, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190124561 A1 |
Apr 25, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62574615 |
Oct 19, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
36/0022 (20130101); H04W 16/04 (20130101); H04W
8/02 (20130101); H04W 76/16 (20180201); H04W
36/14 (20130101); H04W 36/0066 (20130101); H04W
60/00 (20130101); H04W 84/00 (20130101); H04W
48/18 (20130101); H04W 36/0027 (20130101); H04W
48/16 (20130101) |
Current International
Class: |
H04W
36/00 (20090101); H04W 36/14 (20090101); H04W
16/04 (20090101); H04W 8/02 (20090101); H04W
60/00 (20090101); H04W 84/00 (20090101); H04W
48/18 (20090101); H04W 76/16 (20180101); H04W
48/16 (20090101) |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
International Search Report and Written
Opinion--PCT/US2018/049137--ISA/EPO--dated Jan. 22, 2019. cited by
applicant .
NTT Docomo: "TS 23.503: Ol#8a: Pre-Configuration of Mapping between
Application and S-NSSAI", 3GPP Draft, S2-177227 TS
23.503-SLICEMAPPINGPRECONFIGURED, 3rd Generation Partnership
Project (3GPP), Mobile Competence Centre, 650, Route Des Lucioles,
F-06921 Sophia-Antipolis Cedex, France vol. SA WG2. No. Ljubljana,
Slovenia, Oct. 23, 2017-Oct. 27, 2017, Oct. 17, 2017 (Oct. 17,
2017), XP051359896, pp. 1-3, Retrieved from the Internet:
URL:http://www.3gpp.org/ftp/tsg_sa/WG2_Arch/TSGS2 123
Ljubljana/Docs/ [retrieved on Oct. 17, 2017]. cited by applicant
.
Partial International Search
Report--PCT/US2018/049137--ISA/EPO--dated Nov. 29, 2018. cited by
applicant .
Qualcomm Incorporated: "TS 23501: Applicability of UE Slicing
Configuration in Roaming Scenarios", 3GPP Draft, S2-176949 TS
23.501 NSSPROAMINGMERGEIES VI, 3rd Generation Partnership Project
(3GPP), Mobile Competence Centre, 650, Route Des Lucioles, F-06921
Sophia-Antipolis Cedex, France, vol. SA WG2. No. Ljubljana.
Slovenia, Oct. 23, 2017-Oct. 27, 2017, Oct. 17, 2017 (Oct. 17,
2017), XP051359654, 10 Pages, Retrieved from the Internet:
URL:http://www.3gpp.org/ftp/tsg_sa/WG2_Arch/TSGS2_123_Ljubljana/Docs/
[retrieved on Oct. 17, 2017]. cited by applicant.
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Primary Examiner: Pham; Chi H
Assistant Examiner: Huang; Weibin
Attorney, Agent or Firm: Arent Fox LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application claims the benefit of U.S. Provisional Application
Ser. No. 62/574,615, entitled "A MECHANISM TO ENABLE INTERWORKING
BETWEEN 5GS NETWORK SLICING AND EPC CONNECTIVITY" and filed on Oct.
19, 2017, which is expressly incorporated by reference herein in
its entirety.
Claims
What is claimed is:
1. A method of wireless communications, comprising: enabling
network slice selection policies (NSSP) to map applications to
network slices, to a data network name (DNN), and to an access
point name (APN) to be used when a user equipment (UE) is connected
to an evolved packet core (EPC), wherein the APN used in the EPC is
different from the DNN used in a fifth generation core network
(5GC); and mapping the applications.
2. The method of claim 1, wherein the enabling the NSSP to map the
applications to the network slices is performed in response to the
UE connecting to the 5GC.
3. The method of claim 1, further comprising maintaining a mapping
of the network slices, the DNN, and the APN to a packet data unit
(PDU) session identity (ID) for each active PDU session.
4. A wireless communication device, comprising: memory storing
instructions; and a processor in communication with the memory,
wherein the processor is configured to execute the instructions to:
enable network slice selection policies (NSSP) to map applications
to network slices, to a data network name (DNN), and to an access
point name (APN) to be used when a user equipment (UE) is connected
to an evolved packet core (EPC), wherein the APN used in the EPC is
different from the DNN used in a fifth generation core network
(5GC); and map the applications.
5. The wireless communication device of claim 4, wherein the
processor is further configured to enable the NSSP to map the
applications to the network slices in response to the UE connecting
to the 5GC.
6. The wireless communication device of claim 4, wherein the
processor is further configured to maintain a mapping of the
network slices, the DNN, and the APN to a packet data unit (PDU)
session identity (ID) for each active PDU session.
7. A non-transitory computer-readable medium storing computer
executable code, comprising code to: enable network slice selection
policies (NSSP) to map applications to network slices, to a data
network name (DNN), and to an access point name (APN) to be used
when a user equipment (UE) is connected to an evolved packet core
(EPC), wherein the APN used in the EPC is different from the DNN
used in a fifth generation core network (5GC); and map the
applications.
8. The non-transitory computer-readable medium of claim 7, wherein
the NSSP is enabled to map the applications to the network slices
in response to the UE connecting to the 5GC.
9. The non-transitory computer-readable medium of claim 7, further
comprising code to maintain a mapping of the network slices, the
DNN, and the APN to a packet data unit (PDU) session identity (ID)
for each active PDU session.
10. A wireless communication device, comprising: means for enabling
network slice selection policies (NSSP) to map applications to
network slices, to a data network name (DNN), and to an access
point name (APN) to be used when a user equipment (UE) is connected
to an evolved packet core (EPC), wherein the APN used in the EPC is
different from the DNN used in a fifth generation core network
(5GC); and means for mapping the applications.
11. The wireless communication device of claim 10, wherein the NSSP
is enabled to map the applications to the network slices in
response to the UE connecting to the 5GC.
12. The wireless communication device of claim 10, further
comprising means for maintaining a mapping of the network slices,
the DNN, and the APN to a packet data unit (PDU) session identity
(ID) for each active PDU session.
Description
BACKGROUND
Aspects of the present disclosure relate generally to wireless
communication networks, and more particularly, to a mechanism to
enable interworking between fifth generation system (5GS) network
slicing and evolved packet core (EPC) connectivity.
Wireless communication networks are widely deployed to provide
various types of communication content such as voice, video, packet
data, messaging, broadcast, and so on. These systems may be
multiple-access systems capable of supporting communication with
multiple users by sharing the available system resources (e.g.,
time, frequency, and power). Examples of such multiple-access
systems include code-division multiple access (CDMA) systems,
time-division multiple access (TDMA) systems, frequency-division
multiple access (FDMA) systems, orthogonal frequency-division
multiple access (OFDMA) systems, and single-carrier frequency
division multiple access (SC-FDMA) systems.
These multiple access technologies have been adopted in various
telecommunication standards to provide a common protocol that
enables different wireless devices to communicate on a municipal,
national, regional, and even global level. For example, a fifth
generation (5G) wireless communications technology (which can be
referred to as new radio (NR)) is envisaged to expand and support
diverse usage scenarios and applications with respect to current
mobile network generations. In an aspect, 5G communications
technology can include: enhanced mobile broadband addressing
human-centric use cases for access to multimedia content, services
and data; ultra-reliable-low latency communications (URLLC) with
certain specifications for latency and reliability; and massive
machine type communications, which can allow a very large number of
connected devices and transmission of a relatively low volume of
non-delay-sensitive information. As the demand for mobile broadband
access continues to increase, however, further improvements in NR
communications technology and beyond may be desired.
For example, for NR communications technology and beyond, current
interworking between 5GS network slicing and EPC (e.g., support for
fourth generation (4G) wireless communications technology)
connectivity solutions may not be supported or provide a desired
level of speed or customization for efficient operation. Thus,
improvements in wireless communication operations may be
desired.
SUMMARY
The following presents a simplified summary of one or more aspects
in order to provide a basic understanding of such aspects. This
summary is not an extensive overview of all contemplated aspects,
and is intended to neither identify key or critical elements of all
aspects nor delineate the scope of any or all aspects. The sole
purpose of this summary is to present some concepts of one or more
aspects in a simplified form as a prelude to the more detailed
description that is presented later.
In an aspect, the present disclosure includes techniques or
mechanisms to enable interworking between 5GS network slicing and
EPC (e.g., support for 4G) connectivity such that, for example,
existing packet data unit (PDU) sessions are maintained and not
dropped when a user equipment (UE) that uses network slices moves
between a 5G network and a 4G network. In another aspect, the
present disclosure includes techniques or mechanisms to enable
interworking between 5GS network slicing and EPC (e.g., support for
4G) connectivity such that, for example, existing PDU sessions that
provide connectivity to a network slice when a UE that uses network
slices moves between a 5G network and a 4G network are connected to
a dedicated EPC core network that supports the same services
provided by the network slice.
In another aspect, a method of wireless communications is described
that includes enabling Network Slice Selection Policies (NSSP) to
map applications to network slices, to a data network name (DNN),
and to an access point name (APN) to be used when a UE is connected
to an EPC, as an example when the APN used in the EPC is different
from the DNN used in a 5G network; and mapping the
applications.
In another aspect, a method of wireless communications is described
that includes enabling UE functionality to maintain a mapping
between active packet data network (PDN) connections and
corresponding single network slice selection assistance information
(S-NSSAI) in response to the UE moving to an EPC or in response to
new PDN connections being created while the UE is in the EPC; and
providing information about the mapping to an access and mobility
management function (AMF) during a registration procedure.
In yet another aspect, a method of wireless communications is
described that includes enabling an AMF supporting a connectivity
to a variety of network slices to be configured with a mapping
between a set of network slices (e.g. each identified by a S-NSSAI)
in a list of network slices allowed by the network for the UE (i.e.
in an allowed S-NSSAI assigned to UE) to a specific dedicated core
network (DCN) in an EPC; and applying the mapping.
In another aspect, a method of wireless communications is described
that includes enabling a session management function
(SMF)-selection functionality to ensure that an AMF selects the SW
for establishing a PDU session for a UE corresponding to a network
slice (e.g. identified by an S-NSSAI) considering a mapping between
a set of network slices (e.g. each identified by the S-NSSAI) and
DCNs in the EPC, in order to ensure the SW may continue supporting
the connectivity management for the PDU session when the UE moves
the PDU session to the EPC and a specific DCN is selected to serve
the UE based on the mapping between the network slices and the
DCNs; and applying the SW-selection functionality.
In another aspect, a method of wireless communications is described
that includes augmenting a subscribed UE usage type maintained in a
home subscriber server (HSS) with a temporary UE usage type set by
an AMF based on an allowed S-NSSAI; providing the temporary UE
usage type to the HSS when the allowed S-NSSAI is allocated to the
UE; storing, in the HSS, the temporary UE usage type in addition to
the subscribed UE usage type; and, when providing the UE usage type
to a mobility management entity (MME), if the HSS has a stored
temporary UE usage type, the HSS provides the temporary UE usage
type.
In another aspect, a wireless communication device is described
that includes a transceiver, a memory, and a processor in
communication with the memory and the transceiver, wherein the
processor is configured to perform any of the methods described
herein.
In yet another aspect, a wireless communication device is described
that includes one or more means for performing any of the methods
described herein.
In yet another aspect, a computer-readable medium storing computer
code executable by a processor for wireless communications is
described that includes one or more codes executable to perform any
of the methods described herein.
Moreover, the present disclosure also includes apparatus having
components or configured to execute or means for executing the
above-described methods, and computer-readable medium storing one
or more codes executable by a processor to perform the
above-described methods.
To the accomplishment of the foregoing and related ends, the one or
more aspects comprise the features hereinafter fully described and
particularly pointed out in the claims. The following description
and the annexed drawings set forth in detail certain illustrative
features of the one or more aspects. These features are indicative,
however, of but a few of the various ways in which the principles
of various aspects may be employed, and this description is
intended to include all such aspects and their equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosed aspects will hereinafter be described in conjunction
with the appended drawings, provided to illustrate and not to limit
the disclosed aspects, wherein like designations denote like
elements, and in which:
FIG. 1 is a schematic diagram of a wireless communication network
including at least one user equipment (UE) having an interworking
component configured according to this disclosure to interworking
between fifth generation system (5GS) network slicing and evolved
packet core (EPC) connectivity;
FIG. 2 is a block diagram illustrating an example of a non-roaming
architecture for interworking between 5GS and EPC;
FIG. 3 is a flow diagram of an example of a method for interworking
between 5GS network slicing and EPC connectivity;
FIG. 4 is a flow diagram of an example of another method for
interworking between 5GS network slicing and EPC connectivity;
FIG. 5 is a flow diagram of an example of another method for
interworking between 5GS network slicing and EPC connectivity;
FIG. 6 is a flow diagram of an example of another method for
interworking between 5GS network slicing and EPC connectivity;
FIG. 7 is a flow diagram of an example of yet another method for
interworking between 5GS network slicing and EPC connectivity;
FIG. 8 is a schematic diagram of example components of the UE of
FIG. 1; and
FIG. 9 is a schematic diagram of example components of a networking
device to enable interworking between 5GS network slicing and EPC
connectivity.
DETAILED DESCRIPTION
Various aspects are now described with reference to the drawings.
In the following description, for purposes of explanation, numerous
specific details are set forth in order to provide a thorough
understanding of one or more aspects. It may be evident, however,
that such aspect(s) may be practiced without these specific
details. Additionally, the term "component" as used herein may be
one of the parts that make up a system, may be hardware, firmware,
and/or software stored on a computer-readable medium, and may be
divided into other components.
The present disclosure generally relates to a techniques or
mechanisms to enable interworking between fifth generation system
(5GS) network slicing and evolved packet core (EPC) (e.g., support
for fourth generation (4G)) connectivity such that, for example,
existing packet data unit (PDU) sessions are maintained and not
dropped when a user equipment (UE) that uses network slices moves
between a 5G network and a 4G network. In another aspect, the
present disclosure includes techniques or mechanisms to enable
interworking between 5GS network slicing and EPC (e.g., support for
4G) connectivity such that, for example, existing PDU sessions that
provide connectivity to a network slice when a UE that uses network
slices moves between a 5G network and a 4G network and are
connected to a dedicated EPC core network that supports the same
services provided by the network slice.
With the introduction of the complex feature of slicing in 5G
networks, interworking with the EPC for devices in networks without
full 5G radio access network (RAN) coverage or where some services
are available only in the EPC must consider how the functionality
of slicing in the 5GC will interwork when the EPC: (1) supports no
dedicated core network concept, (2) supports Dedicated Core
Networks (DCNs) via Decor, (3) supports DCNs via eDecor (i.e.,
UE-assisted Decor). In particular, solutions are needed to: (1)
define how a set of allowed network slices in the 5G core network
(5GC) for a UE is mapped on one DCN when the UE moves to the EPC,
or how they are handled when the UE moves to an EPC without DCNs,
(2) define how sets that can co-exist in the 5GC but map to
different DCNs are handled in mobility to the EPC, and (3) define
how connectivity to the EPC is mapped to network slices when the UE
moves from the EPC to the 5GC, since the EPC has no concept of
network slices and no network slicing context can be maintained or
supported by EPC network functions.
The solutions described herein for the issues noted above introduce
various components or aspects:
(1) Enhance network slice selection policies (NSSP) to map not only
applications to network slices (e.g., single network slice
selection assistance information (S-NSSAI)) and to a data network
name (DNN), but also to the access point name (APN) to be used when
the UE is in the EPC.
(2) Enhance the UE functionality to maintain the mapping between
active packet data network (PDN) connections and the corresponding
S-NSSAI when the UE moves to the EPC or when new PDN connections
are created while the UE is in the EPC. The UE will use such
information when moving from EPC to 5GC and will provide it to the
access and mobility management function (AMF) during a routing
management (RM) procedure (e.g., registration procedure).
(3) Enhance the AMF to be configured with a mapping between a set
of S-NSSAIs in the allowed S-NSSAI assigned to a UE to a DCN in the
EPC.
(4) Enhance session management function (SMF)-selection
functionality to ensure that the AMF selects an SMF considering the
mapping between S-NSSAIs and DCNs.
(5) Ensure the UE Usage Type maintained in the home subscriber
server (HSS) is augmented with a Temporary UE Usage Type set by the
AMF based on the allowed NSSAI, and pushed to the HSS when an
allowed NSSAI is allocated to the UE. When a mobility management
entity (MME) asks the UE Usage Type from the HSS, if the Temporary
UE Usage Type is set, the HSS provides such value. In this way the
MME can select the DCN serving the UE based on dynamic information
and not just subscription information.
Additional features of the present aspects are described in more
detail below with respect to FIGS. 1-9.
It should be noted that the techniques described herein may be used
for various wireless communication networks such as code-division
multiple access (CDMA), time-division multiple access (TDMA),
frequency-division multiple access (FDMA), orthogonal
frequency-division multiple access (OFDMA), single-carrier
frequency-division multiple access (SC-FDMA), and other systems.
The terms "system" and "network" are often used interchangeably. A
CDMA system may implement a radio technology such as CDMA2000,
Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers
IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and A are
commonly referred to as CDMA2000 1.times., 1.times., etc. IS-856
(TIA-856) is commonly referred to as CDMA2000 1.times.EV-DO, High
Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA)
and other variants of CDMA. A TDMA system may implement a radio
technology such as Global System for Mobile Communications (GSM).
An OFDMA system may implement a radio technology such as Ultra
Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi),
IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM.TM., etc. UTRA and
E-UTRA are part of Universal Mobile Telecommunication System
(UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are
new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE,
LTE-A, and GSM are described in documents from an organization
named "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB
are described in documents from an organization named "3rd
Generation Partnership Project 2" (3GPP2). The techniques described
herein may be used for the systems and radio technologies mentioned
above as well as other systems and radio technologies, including
cellular (e.g., LTE) communications over a shared radio frequency
spectrum band. The description below, however, describes an
LTE/LTE-A system for purposes of example, and LTE terminology is
used in much of the description below, although the techniques are
applicable beyond LTE/LTE-A applications (e.g., to 5G networks or
other next generation communication systems).
The following description provides examples, and is not limiting of
the scope, applicability, or examples set forth in the claims.
Changes may be made in the function and arrangement of elements
discussed without departing from the scope of the disclosure.
Various examples may omit, substitute, or add various procedures or
components as appropriate. For instance, the methods described may
be performed in an order different from that described, and various
steps may be added, omitted, or combined. Also, features described
with respect to some examples may be combined in other
examples.
Referring to FIG. 1, in accordance with various aspects of the
present disclosure, an example wireless communication network 100
includes at least one UE 110 with a modem 140 having an
interworking component 150 configured to support mechanisms to
enable interworking between 5GS network slicing and EPC
connectivity. In some aspects, the interworking component 150 may
include one or more sub components including an application mapping
component 152, a mapping management component 154, SW-selection
functionality component 156, and/or a usage type component 158. In
an example, the application mapping component 152 is configured to
enable NSSP to map applications to network slices, to a DNN, and to
an APN to be used when a UE is connected to an EPC, and mapping the
applications. In an example, the mapping management component 154
is configured to enable UE functionality to maintain a mapping
between active PDN connections and corresponding S-NSSAI in
response to the UE moving to an EPC or in response to new PDN
connections being created while the UE is in the EPC, and provide
information about the mapping to an AMF during a registration
procedure. In another example, the mapping management component 154
is configured to enable an access and mobility management function
(AMF) supporting a connectivity to a variety of network slices to
be configured with a mapping between a set of network slices in an
list of network slices allowed by the network for the UE to a
specific dedicated core network (DCN) in an evolved packet core
(EPC), apply the mapping.
In another example, the SW-selection functionality component 156 is
configured to enable a session management function (SMF)-selection
functionality to ensure that an access and mobility management
function (AMF) selects an SW for establishing a packet data unit
(PDU) session for a user equipment (UE) corresponding to a network
slice considering a mapping between a set of network slices and
dedicated core networks (DCNs) in an evolved packet core (EPC), and
apply the SW-selection functionality.
In another example, the usage type component 158 augment a
subscribed user equipment (UE) usage type maintained in a home
subscriber server (HSS) with a temporary UE usage type set by an
access and mobility management function (AMF) based on an allowed
single network slice selection assistance information (S-NSSAI),
and provide the temporary UE usage type to the HSS when the allowed
S-NSSAI is allocated to the UE.
Further, wireless communication network 100 includes at least one
network device (see e.g., FIG. 9) an interworking component 950
(not shown) that performs network-related operations to support
interworking between 5GS network slicing and EPC connectivity.
The wireless communication network 100 may include one or more base
stations 105, one or more UEs 110, and a core network 115. The core
network 115 may provide user authentication, access authorization,
tracking, internet protocol (IP) connectivity, and other access,
routing, or mobility functions. The base stations 105 may interface
with the core network 115 through backhaul links 120 (e.g., S1,
etc.). The base stations 105 may perform radio configuration and
scheduling for communication with the UEs 110, or may operate under
the control of a base station controller (not shown). In various
examples, the base stations 105 may communicate, either directly or
indirectly (e.g., through core network 115), with one another over
backhaul links 125 (e.g., X1, etc.), which may be wired or wireless
communication links.
The base stations 105 may wirelessly communicate with the UEs 110
via one or more base station antennas. Each of the base stations
105 may provide communication coverage for a respective geographic
coverage area 130. In some examples, the base stations 105 may be
referred to as a base transceiver station, a radio base station, an
access point, an access node, a radio transceiver, a NodeB, eNodeB
(eNB), gNB, Home NodeB, a Home eNodeB, a relay, or some other
suitable terminology. The geographic coverage area 130 for a base
station 105 may be divided into sectors or cells making up only a
portion of the coverage area (not shown). The wireless
communication network 100 may include base stations 105 of
different types (e.g., macro base stations or small cell base
stations, described below). Additionally, the plurality of base
stations 105 may operate according to different ones of a plurality
of communication technologies (e.g., 5G (New Radio or "NR"),
4G/LTE, 3G, Wi-Fi, Bluetooth, etc.), and thus there may be
overlapping geographic coverage areas 130 for different
communication technologies.
In some examples, the wireless communication network 100 may be or
include one or any combination of communication technologies,
including a NR or 5G technology, an LTE, LTE-A or MuLTEfire
technology, a Wi-Fi technology, a Bluetooth technology, or any
other long or short range wireless communication technology. In
LTE/LTE-A/MuLTEfire networks, the term evolved node B (eNB or e
Node B) may be generally used to describe the base stations 105,
while the term UE may be generally used to describe the UEs 110.
The wireless communication network 100 may be a heterogeneous
technology network in which different types of eNBs provide
coverage for various geographical regions. For example, each eNB or
base station 105 may provide communication coverage for a macro
cell, a small cell, or other types of cell. The term "cell" is a
3GPP term that can be used to describe a base station, a carrier or
component carrier associated with a base station, or a coverage
area (e.g., sector, etc.) of a carrier or base station, depending
on context.
A macro cell may generally cover a relatively large geographic area
(e.g., several kilometers in radius) and may allow unrestricted
access by the UEs 110 with service subscriptions with the network
provider.
A small cell may include a relative lower transmit-powered base
station, as compared with a macro cell, that may operate in the
same or different frequency bands (e.g., licensed, unlicensed,
etc.) as macro cells. Small cells may include pico cells, femto
cells, and micro cells according to various examples. A pico cell,
for example, may cover a small geographic area and may allow
unrestricted access by the UEs 110 with service subscriptions with
the network provider. A femto cell may also cover a small
geographic area (e.g., a home) and may provide restricted access
and/or unrestricted access by the UEs 110 having an association
with the femto cell (e.g., in the restricted access case, the UEs
110 in a closed subscriber group (CSG) of the base station 105,
which may include the UEs 110 for users in the home, and the like).
An eNB for a macro cell may be referred to as a macro eNB. An eNB
for a small cell may be referred to as a small cell eNB, a pico
eNB, a femto eNB, or a home eNB. An eNB may support one or multiple
(e.g., two, three, four, and the like) cells (e.g., component
carriers).
The communication networks that may accommodate some of the various
disclosed examples may be packet-based networks that operate
according to a layered protocol stack and data in the user plane
may be based on the IP. A user plane protocol stack (e.g., packet
data convergence protocol (PDCP), radio link control (RLC), MAC,
etc.), may perform packet segmentation and reassembly to
communicate over logical channels. For example, a MAC layer may
perform priority handling and multiplexing of logical channels into
transport channels. The MAC layer may also use hybrid automatic
repeat/request (HARD) to provide retransmission at the MAC layer to
improve link efficiency. In the control plane, the RRC protocol
layer may provide establishment, configuration, and maintenance of
an RRC connection between a UE 110 and the base stations 105. The
RRC protocol layer may also be used for core network 115 support of
radio bearers for the user plane data. At the physical (PHY) layer,
the transport channels may be mapped to physical channels.
The UEs 110 may be dispersed throughout the wireless communication
network 100, and each UE 110 may be stationary or mobile. A UE 110
may also include or be referred to by those skilled in the art as a
mobile station, a subscriber station, a mobile unit, a subscriber
unit, a wireless unit, a remote unit, a mobile device, a wireless
device, a wireless communications device, a remote device, a mobile
subscriber station, an access terminal, a mobile terminal, a
wireless terminal, a remote terminal, a handset, a user agent, a
mobile client, a client, or some other suitable terminology. A UE
110 may be a cellular phone, a smart phone, a personal digital
assistant (PDA), a wireless modem, a wireless communication device,
a handheld device, a tablet computer, a laptop computer, a cordless
phone, a smart watch, a wireless local loop (WLL) station, an
entertainment device, a vehicular component, a customer premises
equipment (CPE), or any device capable of communicating in wireless
communication network 100. Additionally, a UE 110 may be Internet
of Things (IoT) and/or machine-to-machine (M2M) type of device,
e.g., a low power, low data rate (relative to a wireless phone, for
example) type of device, that may in some aspects communicate
infrequently with wireless communication network 100 or other UEs.
A UE 110 may be able to communicate with various types of base
stations 105 and network equipment including macro eNBs, small cell
eNBs, macro gNBs, small cell gNBs, relay base stations, and the
like.
The UE 110 may be configured to establish one or more wireless
communication links 135 with one or more of the base stations 105.
The wireless communication links 135 shown in wireless
communication network 100 may carry uplink (UL) transmissions from
a UE 110 to a base station 105, or downlink (DL) transmissions,
from a base station 105 to a UE 110. The DL transmissions may also
be called forward link transmissions while the UL transmissions may
also be called reverse link transmissions. Each wireless
communication link 135 may include one or more carriers, where each
carrier may be a signal made up of multiple sub-carriers (e.g.,
waveform signals of different frequencies) modulated according to
the various radio technologies described above. Each modulated
signal may be sent on a different sub-carrier and may carry control
information (e.g., reference signals, control channels, etc.),
overhead information, user data, etc. In an aspect, the wireless
communication links 135 may transmit bidirectional communications
using frequency division duplex (FDD) (e.g., using paired spectrum
resources) or time division duplex (TDD) operation (e.g., using
unpaired spectrum resources). Frame structures may be defined for
FDD (e.g., frame structure type 1) and TDD (e.g., frame structure
type 2). Moreover, in some aspects, the wireless communication
links 135 may represent one or more broadcast channels.
In some aspects of the wireless communication network 100, the base
stations 105 or the UEs 110 may include multiple antennas for
employing antenna diversity schemes to improve communication
quality and reliability between the base stations 105 and the UEs
110. Additionally or alternatively, the base stations 105 or the
UEs 110 may employ multiple input multiple output (MIMO) techniques
that may take advantage of multi-path environments to transmit
multiple spatial layers carrying the same or different coded
data.
The wireless communication network 100 may support operation on
multiple cells or carriers, a feature which may be referred to as
carrier aggregation (CA) or multi-carrier operation. A carrier may
also be referred to as a component carrier (CC), a layer, a
channel, etc. The terms "carrier," "component carrier," "cell," and
"channel" may be used interchangeably herein. A UE 110 may be
configured with multiple downlink CCs and one or more uplink CCs
for carrier aggregation. CA may be used with both FDD and TDD
component carriers. The base stations 105 and the UEs 110 may use
spectrum up to Y MHz (e.g., Y=5, 10, 15, or 20 MHz) bandwidth per
carrier allocated in a carrier aggregation of up to a total of Yx
MHz (x=number of component carriers) used for transmission in each
direction. The carriers may or may not be adjacent to each other.
Allocation of carriers may be asymmetric with respect to DL and UL
(e.g., more or less carriers may be allocated for DL than for UL).
The CCs may include a primary CC and one or more secondary CC. A
primary CC may be referred to as a primary cell (PCell) and a
secondary CC may be referred to as a secondary cell (SCell).
The wireless communications network 100 may further include the
base stations 105 operating according to Wi-Fi technology, e.g.,
Wi-Fi access points, in communication with the UEs 110 operating
according to Wi-Fi technology, e.g., Wi-Fi stations (STAs) via
communication links in an unlicensed frequency spectrum (e.g., 5
GHz). When communicating in an unlicensed frequency spectrum, the
STAs and AP may perform a clear channel assessment (CCA) or listen
before talk (LBT) procedure prior to communicating in order to
determine whether the channel is available.
Additionally, one or more of the base stations 105 and/or the UEs
110 may operate according to a NR or 5G technology referred to as
millimeter wave (mmW or mmwave) technology. For example, mmW
technology includes transmissions in mmW frequencies and/or near
mmW frequencies. Extremely high frequency (EHF) is part of the
radio frequency (RF) in the electromagnetic spectrum. EHF has a
range of 30 GHz to 300 GHz and a wavelength between 1 millimeter
and 10 millimeters. Radio waves in this band may be referred to as
a millimeter wave. Near mmW may extend down to a frequency of 3 GHz
with a wavelength of 100 millimeters. For example, the super high
frequency (SHF) band extends between 3 GHz and 30 GHz, and may also
be referred to as centimeter wave. Communications using the mmW
and/or near mmW radio frequency band has extremely high path loss
and a short range. As such, the base stations 105 and/or the UEs
110 operating according to the mmW technology may utilize
beamforming in their transmissions to compensate for the extremely
high path loss and short range.
Additional details related to the various aspects of techniques or
mechanisms to enable interworking between 5GS network slicing and
EPC (e.g., support for 4G) connectivity are described below.
DCN in EPC
For 4G systems, EPC supports dedicated core networks or DECOR. This
feature enables an operator to deploy multiple DCNs within a public
land mobile network (PLMN) with each DCN consisting of one or
multiple core network (CN) nodes. Each DCN may be dedicated to
serve specific type(s) of subscriber. This is an optional feature
and enables DCNs to be deployed for one or multiple radio access
technologies (RATs) (e.g., Global System for Mobile communications
(GSM) Enhanced Data rates for GSM Evolution (EDGE) Radio Access
Network (GERAN), Universal Terrestrial Radio Access Network
(UTRAN), evolved UTRAN (E-UTRAN), Wideband E-UTRAN (WB-E-UTRAN) and
Narrow Band Internet-of-Things (NB-IoT)). There can be several
motivations for deploying DCNs, e.g., to provide DCNs with specific
characteristics/functions or scaling, to isolate specific UEs or
subscribers (e.g., machine-to-machine (M2M) subscribers,
subscribers belonging to a specific enterprise or separate
administrative domain, etc.). It is to be understood that a UE
generally is connected to only one DCN at a time.
A DCN comprises one or more MME/serving General Packet Radio
Service (GPRS) support node (SGSN) and it may comprise of one or
more serving gateway (SGW)/PDN gateway (PGW)/policy and changing
rules function (PCRF). This feature enables subscribers to be
allocated to and served by a DCN based on subscription information
("UE Usage Type"). This feature handles both DCN selections without
any specific UE functionality, that is, it works also with UEs of
earlier releases and UE assisted DCN selection. The main specific
functions are for routing and maintaining UEs in their respective
DCN. The following deployment scenarios are supported for DCN. In
some deployment scenarios, DCNs may be deployed to support one RAT
only, (e.g., only dedicated MMES are deployed to support E-UTRAN
and dedicated SGSNs are not deployed), to support multiple RATs, or
to support all RATs.
In some deployment scenarios, networks deploying DCNs may have a
default DCN, which is managing UEs for which a DCN is not available
or if sufficient information is not available to assign a UE to a
DCN. One or multiple DCNs may be deployed together with a default
DCN that all share the same RAN.
In some deployment scenarios, the architecture supports scenarios
where the DCN is only deployed in a part of the PLMN (e.g. only for
one RAT or only in a part of the PLMN area). Such heterogeneous or
partial deployment of DCNs may, depending on operator deployment
and configuration, result in service with different characteristics
or functionality, depending on whether the UE is inside or outside
the service area or RAT that supports the DCN. In some examples,
heterogeneous or partial deployment of DCNs may result in increased
occurrence of UEs first being served by a CN node in the default
DCN and then being redirected to a CN node in the DCN that serves
the UE when the UE moves from areas outside of DCN coverage to an
area of DCN coverage. It may also result in an increased re-attach
rate in the network. As this has impacts on the required capacity
of the default CN nodes deployed at edge of DCN coverage, it is not
recommended to deploy DCNs heterogeneously or partially.
In some deployment scenarios, even if the DCN is not deployed to
serve a particular RAT or service area of PLMN, the UE in that RAT
or service area may still be served by a PGW from the DCN.
A high level overview for supporting DCNs is provided below. In
some examples, an optional subscription information parameter ("UE
Usage Type") is used in the selection of a DCN. An operator
configures which of his DCN(s) serves which UE Usage Type(s). The
HSS provides the "UE Usage Type" value in the subscription
information of the UE to the MME/SGSN. Both standardized and
operator specific values for UE Usage Type are possible.
In some examples, the serving network selects the DCN based on the
operator configured (UE Usage Type to DCN) mapping, other locally
configured operator's policies and the UE related context
information available at the serving network (e.g. information
about roaming). UEs with different UE Usage Type values may be
served by the same DCN. Moreover, UEs that share the same UE Usage
Type value may be served by different DCNs.
In some examples, if the configuration shows no DCN for the
specific "UE Usage Type" value in the subscription information,
then the serving MME/SGSN serves the UE by the default DCN or
selects a DCN using serving operator specific policies.
In some examples, the "UE Usage Type" is associated with the UE
(describing its usage characteristic), that is, there is only one
"UE Usage Type" per UE subscription.
In some examples, for each DCN, one or more CN nodes may be
configured as part of a pool.
In some examples, for MME, the MME Group Identification(s) (ID(s))
or MMEGI(s) identifies a DCN within the PLMN. For SGSNs, a group
identifier(s) identifies a DCN within the PLMN. That is, the group
of SGSNs that belong to a DCN within a PLMN. This identifier may
have the same format as Network Resource Identifier (NRI) (e.g. an
NRI value that does not identify a specific SGSN node in the
serving area) in which case it is called "Null-NRI" or it may have
a format independent of NRI, in which case it is called "SGSN Group
ID". The "Null-NRI" or "SGSN Group ID" is provided by an SGSN to
RAN which triggers a Network Node Selection Function (NNSF)
procedure to select an SGSN from the group of SGSNs corresponding
to the Null-NRI/SGSN Group ID.
In some examples, SGSN Group IDs enable handling deployment
scenarios where in a service area all NRI values are allocated to
SGSNs and hence no NM value remains that can be used as
Null-NRI.
In some examples, the dedicated MME/SGSN that serves the UE selects
a dedicated S-GW and P-GW based on UE Usage Type.
In some examples, at initial access to the network if sufficient
information is not available for RAN to select a specific DCN, the
RAN may selects a CN node from the default DCN. A redirection to
another DCN may then be required.
In some examples, to redirect a UE from one DCN to a different DCN,
a redirection procedure via RAN may be used to forward a Non-Access
Stratum (NAS) message of the UE to the target DCN.
In some examples, all selection functions are aware of DCN(s),
including the NNSF of RAN nodes, for selecting and maintaining the
appropriate DCN for the UEs.
There is also UE-assisted dedicated core network selection or
eDECOR. This feature is to reduce the need for DECOR reroute by
using an indication (DCN-ID) sent from the UE and used by RAN to
select the correct DCN. The DCN-ID can be assigned to the UE by the
serving PLMN and can be stored in the UE per PLMN ID. Both
standardized and operator specific values for DCN-ID are possible.
The UE can use the PLMN specific DCN-ID whenever a PLMN specific
DCN-ID is stored for the target PLMN.
A home PLMN (HPLMN) may provision the UE with a single default
standardized DCN-ID which shall be used by the UE only if the UE
has no PLMN specific DCN-ID of the target PLMN. When a UE
configuration is changed with a new default standardized DCN-ID,
the UE shall delete all stored PLMN specific DCN-IDs.
The UE provides the DCN-ID to RAN at registration to a new location
in the network, that is, in the Attach, TAU and RAU. RAN selects
serving node (MME or SGSN) based on the DCN-ID provided by the UE
and configuration in RAN. For E-UTRAN the eNB is configured with
DCNs supported by the connected MMES at the setup of the S1
connection. For UTRAN and GERAN the BSS/RNC is configured with the
DCNs supported in the connected SGSN via O&M. Both standardized
DCN-IDs and PLMN specific DCN-IDs can in the RAN configuration be
assigned to the same network. If information provided by the UE
(e.g., Globally Unique Temporary ID (GUTI), NRI, etc.) indicates a
node (MME or SGSN) for attach/TAU/RAU and a serving node (MME or
SGSN) corresponding to the UE information can be found by the RAN
node, the normal node selection shall take precedence over the
selection based on DCN-ID. At registration the MME/SGSN may check
if the correct DCN is selected. If the MME/SGSN concludes that the
selected DCN is not the correct DCN, a DECOR reroute is performed
and the SGSN/MME in the new DCN assigns a new DCN-ID to the UE. The
serving MME/SGSN can also assign a new DCN-ID to the UE if, for
example, the DCN-ID in the UE has become obsolete or when the UE
Usage Type has been updated in the subscription information leading
to a change of DCN. This is performed as part of the GUTI
Reallocation procedure.
Slicing in 5GC
A network slice (or just a slice) is defined within a PLMN and
includes the Core Network Control Plane and User Plane Network
Functions, and, in the serving PLMN, at least one of the following:
a New Generation (NG) RAN, or a Non-3GPP Interworking Function
(N3IWF) to the non-3GPP Access Network. A network slice can be
viewed as a virtual end-to-end network (e.g., network
virtualization). A device, such as a UE, can connect to multiple
network slices at the same time. Instances of network slices can
include instances for IoT, public safety, eMBB, and others.
Moreover, by enabling Network Slicing, an operator can rent
services to different clients. For example, there can be an eMBB
slice and/or a V2X slice can be supported, with the latter possibly
being an automotive client-specific instance.
Network slices may differ for supported features and network
functions optimizations. The operator may deploy multiple Network
Slice instances delivering exactly the same features but for
different groups of UEs, e.g., as they deliver a different
committed service and/or because they may be dedicated to a
customer.
A single UE can simultaneously be served by one or more Network
Slice instances via a 5G-AN. A single UE may be served by, for
example, at most eight Network Slices at a time. The AMF instance
serving the UE logically belongs to each of the Network Slice
instances serving the UE, that is, this AMF instance is common to
the Network Slice instances serving a UE. The AMF can be viewed as
the architecture's common point to the various Network Slices.
The selection of the set of Network Slice instances, where each of
the Network Slice instances can correspond to one or more Allowed
S-NSSAIs, for a UE is triggered by the first contacted AMF in a
registration procedure normally by interacting with the NSSF, and
it may lead to change of AMF.
SMF discovery and selection within the selected Network Slice
instance is initiated by the AMF when a SM message to establish a
packet data unit (PDU) session is received from the UE. The NF
repository function (NRF) is used to assist the discovery and
selection tasks of the required network functions for the selected
Network Slice instance.
A PDU session belongs to one and only one specific Network Slice
instance per PLMN. Different Network Slice instances do not share a
PDU session, though different slices may have slice-specific PDU
sessions using the same DNN.
In some aspects, identification and selection of a Network Slice is
based on the S-NSSAI and the NSSAI. In an example, an S-NSSAI
identifies a Network Slice. An S-NSSAI may be comprised of: a
Slice/Service type (SST), which refers to the expected Network
Slice behavior in terms of features and services and/or A Slice
Differentiator (SD), which is optional information that complements
the Slice/Service type(s) to differentiate amongst multiple Network
Slices of the same Slice/Service type.
The S-NSSAI can have standard values or PLMN-specific values.
S-NSSAIs with PLMN-specific values are associated to the PLMN ID of
the PLMN that assigns it. An S-NSSAI shall not be used by the UE in
access stratum procedures in any PLMN other than the one to which
the S-NSSAI is associated.
The NSSAI is a collection of S-NSSAIs. There can be, for example,
at most 8 S-NSSAIs in the NSSAI sent in signaling messages between
the UE and the Network. Each S-NSSAI assists the network in
selecting a particular Network Slice instance. The same Network
Slice instance may be selected by means of different S-NSSAIs.
Based on the operator's operational or deployment needs, multiple
Network Slice instances of a given S-NSSAI may be deployed in the
same or in different registration areas. When multiple Network
Slice instances of a given S-NSSAI are deployed in the same
registration area, the AMF instance serving the UE may logically
belong to more than one Network Slice instances of that S-NSSAI,
i.e. this AMF instance may be common to multiple Network Slice
instances of that S-NSSAI. When a S-NSSAI is supported by more than
one Network Slice instance in a PLMN, any of the Network Slice
instances supporting the same S-NSSAI in a certain area may serve,
as a result of the Network Slice instance selection procedure, a UE
which is allowed to use this S-NSSAI. Upon association with an
S-NSSAI, the UE is served by the same Network Slice instance for
that S-NSSAI until cases occur where, e.g., Network Slice instance
is no longer valid in a given registration area, or a change in
UE's Allowed NSSAI occurs etc.
The selection of a Network Slice instance(s) serving a UE and the
Core Network Control Plane and user plane Network Functions
corresponding to the Network Slice instance is the responsibility
of 5GC. The (R)AN may use Requested NSSAI in access stratum
signaling to handle the UE Control Plane connection before the 5GC
informs the (R)AN of the Allowed NSSAI. The Requested NSSAI is not
used by the RAN for routing when the UE provides also a Temporary
User ID. When a UE is successfully registered, the CN informs the
(R)AN by providing the whole Allowed NSSAI for the Control Plane
aspects. When a PDU Session for a given S-NSSAI is established
using a specific Network Slice instance, the CN provides to the
(R)AN the S-NSSAI corresponding to this Network Slice instance to
enable the RAN to perform access specific functions. Subscription
information may contain multiple S-NSSAIs. One or more of the
Subscribed S-NSSAIs can be marked as default S-NSSAI. At most eight
S-NSSAIs can be marked as default S-NSSAI. However, the UE may
subscribe to more than eight S-NSSAIs. If an S-NSSAI is marked as
default, then the network is expected to serve the UE with the
related Network Slice when the UE does not send any valid S-NSSAI
to the network in a Registration Request message. Subscription
Information for each S-NSSAI may contain multiple DNNs and one
default DNN. The NSSAI the UE provides in the Registration Request
is verified against the user's subscription data.
UE NSSAI Configuration and NSSAI Storage Aspects
A UE can be configured by the HPLMN with a Configured NSSAI per
PLMN. A Configured NSSAI can be PLMN-specific and the HPLMN
indicates to what PLMN(s) each Configured NSSAI applies, including
whether the Configured NSSAI applies to all PLMNs, that is, the
Configured NSSAI conveys the same information regardless of the
PLMN the UE is accessing (e.g., this could be possible for NSSAIs
containing only standardized S-NSSAIs). When providing a Requested
NSSAI to the network upon registration, the UE in a given PLMN
shall only use S-NSSAIs belonging to the Configured NSSAI, if any,
of that PLMN. Upon successful completion of a UE's registration
procedure, the UE may obtain from the AMF an Allowed NSSAI for this
PLMN, which may include one or more S-NSSAIs. These S-NSSAIs are
valid for the current Registration Area provided by the serving AMF
the UE has registered with and can be used simultaneously by the UE
(e.g., up to the maximum number of simultaneous Network Slices or
PDU sessions). The UE may also obtain from the AMF one or more
temporarily or permanently rejected S-NSSAIs.
The Allowed NSSAI can take precedence over the Configured NSSAI for
this PLMN. The UE can use only the S-NSSAI(s) in the Allowed NSSAI
corresponding to a Network Slice for the subsequent procedures in
the serving PLMN.
In an aspect, the UE may store (S)NSSAIs based on the type of
(S)NSSAI. For example, When the UE is provisioned with a Configured
NSSAI for a PLMN in the UE, the Configured NSSAI may be stored in
the UE until a new Configured NSSAI for this PLMN is provisioned in
the UE by the HPLMN: when provisioned with a new Configured NSSAI
for a PLMN, the UE is to both replace any stored Configured NSSAI
for this PLMN with the new Configured NSSAI, and delete any stored
Allowed NSSAI and rejected S-NSSAI for this PLMN.
In some examples, when an Allowed NSSAI for a PLMN is received, the
Allowed NSSAI may be stored in the UE, including when the UE is
turned off, until a new Allowed NSSAI for this PLMN is received.
When a new Allowed NSSAI for a PLMN is received, the UE may replace
any stored Allowed NSSAI for this PLMN with this new Allowed
NSSAI.
In some examples, when a temporarily rejected S-NSSAI for a PLMN is
received, the temporarily rejected S-NSSAI may be stored in the UE
while RM-REGISTERED.
In some examples, when a permanently rejected S-NSSAI for a PLMN is
received, permanently rejected S-NSSAI may be stored in the UE
while RM-REGISTERED.
One or multiple of the S-NSSAIs in the Allowed NSSAI provided to
the UE can have non-standardized values, which may not be a part of
the UE's NSSAI configuration. In such cases, the Allowed NSSAI
includes mapping information how the S-NSSAIs in the Allowed
S-NSSAI correspond to S-NSSAI(s) in the Configured NSSAI in the UE.
The UE uses this mapping information for its internal operation
(e.g., finding an appropriate network slice for UE's services).
Specifically, a UE application, which is associated with an S-NSSAI
as per NSSP, is further associated with the corresponding S-NSSAI
from the Allowed NSSAI.
In some aspects, User Plane connectivity to a Data Network is
established via a Network Slice instance(s). In an example, the
establishment of User Plane connectivity to a Data Network via a
Network Slice instance(s) comprises: performing a RM procedure to
select an AMF that supports the required Network Slices and
establishing one or more PDU session to the required Data network
via the Network Slice Instance(s).
In some aspects, a Serving AMF may be selected to support the
Network Slices. In an example, when a UE registers with a PLMN, if
the UE for this PLMN has a Configured NSSAI or an Allowed NSSAI,
the UE may provide to the network in RRC and NAS layers a Requested
NSSAI containing the S-NSSAI(s) corresponding to the Network
Slice(s) to which the UE wishes to register, in addition to the
Temporary User ID if one was assigned to the UE. The Requested
NSSAI may be either: (a) the Configured-NSSAI, or a subset thereof
as described below, if the UE has no Allowed NSSAI for the serving
PLMN; (b) the Allowed-NSSAI, or a subset thereof as described
below, if the UE has an Allowed NSSAI for the serving PLMN; or (c)
the Allowed-NSSAI, or a subset thereof as described below, plus one
or more S-NSSAIs from the Configured-NSSAI for which no
corresponding S-NSSAI is present in the Allowed NSSAI and that were
not previously permanently rejected (as defined below) by the
network.
In some examples, the subset of Configured-NSSAI provided in the
Requested NSSAI may consist of one or more S-NSSAI(s) in the
Configured NSSAI applicable to this PLMN, if the S-NSSAI was not
previously permanently rejected (as defined below) by the network,
or was not previously added by the UE in a Requested NSSAI.
In some examples, the subset of Allowed NSSAI provided in the
Requested NSSAI may consist of one or more S-NSSAI(s) in the last
Allowed NSSAI for this PLMN.
In an aspect, the UE may provide in the Requested NSSAI an S-NSSAI
from the Configured NSSAI that the UE previously provided to the
serving PLMN in the present Registration Area if the S-NSSAI was
not previously permanently rejected (as defined below) by the
network.
In some examples, the UE can include the Requested NSSAI at RRC
Connection Establishment and in NAS messages. The RAN can route the
NAS signaling between this UE and an AMF selected using the
Requested NSSAI obtained during RRC Connection Establishment. If
the RAN is unable to select an AMF based on the Requested NSSAI,
the RAN may route the NAS signaling to an AMF from a set of default
AMFs.
In some examples, when a UE registers with a PLMN, if for this PLMN
the UE has no Configured NSSAI or Allowed NSSAI, the RAN may route
all NAS signaling from/to this UE to/from a default AMF. In an
example, the UE may not indicate any NSSAI in RRC Connection
Establishment or Initial NAS message unless it has a Configured
NSSAI or Allowed NSSAI for the corresponding PLMN. When receiving
from the UE a Requested NSSAI and a 5G-S-TMSI in RRC, if the RAN
can reach an AMF corresponding to the 5G-S-TMSI, then the RAN may
forward the request to this AMF. Otherwise, the RAN may select a
suitable AMF based on the Requested NSSAI provided by the UE and
may forward the request to the selected AMF. If the RAN is not able
to select an AMF based on the Requested NSSAI, then the request may
be sent to a default AMF.
In an aspect, when the AMF selected by the AN receives the UE
Initial Registration request: (a) the AMF, as part of the
registration procedure, may query the Unified Data Management (UDM)
to retrieve UE subscription information including the Subscribed
S-NSSAIs; (b) the AMF may verify whether the S-NSSAI(s) in the
Requested NSSAI are permitted based on the Subscribed S-NSSAIs; (c)
the AMF, when the UE context in the AMF does not yet include an
Allowed NSSAI, may query the NSSF (see (B) below for subsequent
handling), except in the case when, based on configuration in this
AMF, the AMF is allowed to determine whether it can serve the UE
(see (A) below for subsequent handling). In an example, this
configuration may depend on operator's policy; or (d) the AMF, when
the UE context in the AMF already includes an Allowed NSSAI, based
on configuration for this AMF, may determine whether the AMF can
serve the UE (see (A) below for subsequent handling). This
configuration may depend on the operator's policy.
(A) Depending on fulfilling the configuration as described above,
the AMF may be allowed to determine whether it can serve the UE,
and the following may be performed: The AMF may check whether the
AMF can serve all the S-NSSAI(s) from the Requested NSSAI present
in the Subscribed S-NSSAIs, or all the S-NSSAI(s) marked as default
in the Subscribed S-NSSAIs in case no Requested NSSAI was provided.
If this is the case, the AMF may remain the serving AMF for the UE.
The Allowed NSSAI may then be composed of the list of S-NSSAI(s) in
the Requested NSSAI permitted based on the Subscribed S-NSSAIs, or,
if no Requested NSSAI was provided, all the S-NSSAI(s) marked as
default in the Subscribed S-NSSAIs (see (C) below for subsequent
handling). If this is not the case, the AMF may query the NSSF (see
(B) below for subsequent handling).
(B) When the AMF needs to query the NSSF, as described above, the
following may be performed: the AMF may query the NSSF, with the
Requested NSSAI, the Subscribed S-NSSAIs, the PLMN ID of the SUPI,
the location information, and/or possibly access technology being
used by the UE. Based on this information, local configuration, and
other locally available information including RAN capabilities in
the Registration Area, the NSSF may perform the following: (a) the
NSSF may select the Network Slice instance(s) to serve the UE. When
multiple Network Slice instances in the registration area are able
to serve a given S-NSSAI, based on operator's configuration, the
NSSF may select one of them to serve the UE, or the NSSF may defer
the selection of the Network Slice instance until a NF/service
within the Network Slice instance needs to be selected; (b) the
NSSF may determine the target AMF Set to be used to serve the UE,
or, based on configuration, the list of candidate AMF(s), possibly
after querying the NRF; (c) the NSSF may determine the Allowed
NSSAI, possibly taking also into account the availability of the
Network Slice instances that are able to serve the S-NSSAI(s) in
the Allowed NSSAI in the current registration area; (d) based on
operator configuration, the NSSF may determine the NRF(s) to be
used to select NFs/services within the selected Network Slice
instance(s); (e) the NSSF may perform additional processing to
determine the Allowed NSSAI in roaming scenarios; (f) the NSSF may
return to the current AMF the Allowed NSSAI and the target AMF Set,
or, based on configuration, the list of candidate AMF(s). The NSSF
may return the NRF(s) to be used to select NFs/services within the
selected Network Slice instance(s). The NSSF may also return
information regarding rejection causes for S-NSSAI(s) not included
in the Allowed NSSAI which were part of the Requested NSSAI; (g)
the AMF, depending on the available information and based on
configuration, may query the NRF with the target AMF Set. The NRF
returns a list of candidate AMFs; or (h) the AMF, if rerouting to a
target serving AMF is necessary, may reroute the Registration
Request to a target serving AMF
(C) The serving AMF can return to the UE the Allowed NSSAI. The AMF
may also indicate to the UE for Requested S-NSSAI(s) not included
in the Allowed NSSAI, whether the rejection is permanent (e.g. the
S-NSSAI is not supported in the PLMN) or temporary (e.g. the
S-NSSAI is not currently available in the Registration Area). Upon
successful Registration, the UE may be provided with a 5G Secondary
Temporary Mobile Subscriber Identity (TMSI) (5G-S-TMSI) by the
serving AMF. The UE may include this 5G-S-TMSI in any RRC
Connection Establishment during subsequent initial accesses to
enable the RAN to route the NAS signaling between the UE and the
appropriate AMF.
If the UE receives an Allowed NSSAI from the serving AMF, the UE
may store this new Allowed NSSAI and override any previously stored
Allowed NSSAI for this PLMN.
In an aspect, the set of Network Slice(s) for a UE may be modified.
The set of Network Slices for a UE can be changed at any time while
the UE is registered with a network, and may be initiated by the
network, or the UE under certain conditions as described below. In
some examples, the registration area allocated by the AMF to the UE
may have homogeneous support for network slices.
The network, based on local policies, subscription changes and/or
UE mobility, operational reasons (e.g., a Network Slice instance is
no longer available), may change the set of Network Slice(s) to
which the UE is registered and provide the UE new Allowed NSSAI.
The network may perform such change during a Registration procedure
or trigger a notification towards the UE of the change of the
Network Slices using a Generic UE Configuration Update procedure.
The new Allowed NSSAI may then be determined (an AMF Relocation may
be needed). The AMF may provide the UE with the new Allowed NSSAI
and TAI list, and: (a) if the changes to the Allowed NSSAI do not
require the UE to perform a registration procedure: (1) the AMF may
indicate that acknowledgement is required, but does not indicate
the need to perform a registration procedure; (2) the UE may
respond with a UE configuration update complete message for the
acknowledgement; and/or (3) the UE may respond with a UE
configuration update complete message for the acknowledgement; (b)
if the changes to the Allowed NSSAI require the UE to perform a
registration procedure (e.g., the new S-NSSAIs require a separate
AMF that cannot be determined by the current serving AMF): (1) the
serving AMF may indicate to the UE that a current 5G-GUTI is
invalid and the need for the UE to perform a registration procedure
after entering CM-IDLE state. The AMF shall release the NAS
signaling connection to the UE to allow to enter CM-IDLE based on
local policies (e.g. immediately or delayed release). The UE shall
not perform a Registration procedure before entering Connection
Management (CM)-IDLE state; and/or (2) The UE initiates a
registration procedure after the UE enters CM-IDLE state. The UE
may include subscription Permanent Identification (SUPI) and new
Allowed NSSAI in the registration in this case.
When a Network Slice used for one or multiple PDU Sessions is no
longer available for a UE, in addition to sending the new Allowed
NSSAI to the UE, the following may apply: (a) in the network, if
the Network Slice is no longer available under the same AMF (e.g.
due to UE subscription change), the AMF may indicate to the SMF(s)
corresponding to the relevant S-NSSAI to autonomously release the
UE's SM context; (b) in the network, if the Network Slice becomes
no longer available with AMF relocation (e.g. due to Registration
Area change), the new AMF may indicate to the old AMF that the PDU
Session(s) associated with the relevant S-NSSAI can be released,
and the old AMF informs the corresponding SMF(s) to autonomously
release the UE's SM context; or (c) in the UE, the PDU session(s)
context may be implicitly released after receiving the Allowed
NSSAI in the Registration Accept message.
In some examples, the UE may use UE Configuration (e.g., network
slice security policy or NSSP) to determine whether ongoing traffic
can be routed over existing PDU sessions belonging to other Network
Slices or may establish new PDU session(s) associated with
same/other Network Slice.
In order to change the set of S-NSSAIs being used, the UE can
initiate a Registration procedure.
Change of set of S-NSSAIs to which the UE is registered (whether UE
or Network initiated) may lead to AMF change subject to operator
policy.
In an aspect, AMF Relocation may be due to Network Slice(s)
Support. In an example, during a Registration procedure in a PLMN,
in case the network decides that the UE should be served by a
different AMF based on Network Slice(s) aspects, then the AMF that
first received the Registration Request may redirect the
Registration request to another AMF via the RAN or via direct
signaling between the initial AMF and the target AMF. The
redirection message sent by the AMF via the RAN may include
information for selection of a new AMF to serve the UE.
For a UE that is already registered, the system may support a
redirection initiated by the network of a UE from its serving AMF
to a target AMF due to Network Slice(s) considerations (e.g., the
operator has changed the mapping between the Network Slice
instances and their respective serving AMF(s)). In some examples,
operator policy may determine whether redirection between AMFs is
allowed.
In an aspect, a PDU session may be connected to a required Network
Slice Instance(s). The establishment of a PDU session in a Network
Slice to a DN allows data transmission in a Network Slice. A Data
Network may be associated to an S-NSSAI and a DNN.
In an example, the network operator (e.g., HPLMN) may provision the
UE with NSSP. The NSSP includes one or more NSSP rules each one
associating an application with a certain S-NSSAI. A default rule
which matches all applications to a S-NSSAI may also be included.
When a UE application associated with a specific S-NSSAI requests
data transmission, then: if the UE has one or more PDU sessions
established corresponding to the specific S-NSSAI, the UE may route
the user data of this application in one of these PDU sessions,
unless other conditions in the UE prohibit the use of these PDU
sessions. If the application provides a DNN, then the UE may also
consider this DNN to determine which PDU session to use.
The UE can store the NSSP until a new NSSP is provided to the UE by
the HPLMN. If the UE does not have a PDU session established with
this specific S-NSSAI, the UE may request a new PDU session
corresponding to this S-NSSAI and with the DNN that may be provided
by the application. In order for the RAN to select a proper
resource for supporting network slicing in the RAN, the RAN may be
aware of the Network Slices used by the UE.
In an example, if a Network Slice instance was not selected during
the Registration procedure for this specific S-NSSAI, the AMF may
query the NSSF with this specific S-NSSAI, location information,
PLMN ID of the SUPI to select the Network Slice instance to serve
the UE and to determine the NRF to be used to select NFs/services
within the selected Network Slice instance.
In an example, the AMF may query the NRF to select an SMF in a
Network Slice instance based on S-NSSAI, DNN and other information
(e.g. UE subscription and local operator policies), when the UE
triggers the establishment of a PDU session. The selected SMF may
establish a PDU session based on S-NSSAI and DNN.
In an example, when the AMF belongs to multiple Network Slices,
based on configuration, the AMF may use an NRF at the appropriate
level for the SMF selection.
In an aspect, Network Slicing may be performed through interworking
with evolved packet system (EPS). A 5GC which supports Network
Slicing might need to interwork with the EPS in the 5GC's PLMN or
in other PLMNs, and the EPC may support the DCN in which MME
selection may be assisted by a DCN-ID provided by the UE to the
RAN. If the UE is in Evolved CM (ECM)-IDLE or CM-IDLE state,
mobility may trigger a Tracking Area Update (TAU) (or Attach, if it
is the first mobility event in the target system) in EPS and a
Registration procedure in 5GS. These procedures are sufficient to
place the UE in the right DCN or (set of) Network Slice(s).
For Connected mode mobility/interworking 5GC to EPC and vice versa
(e.g., EPC to 5GC): when a UE CM state in the AMF is CM-CONNECTED
in 5GC and a handover to EPS occurs, the AMF may select the target
MME and may forward the UE context to the selected MME over an
MME-AMF Interface (see e.g., FIG. 2). The handover procedure may
then be executed. When the handover completes, the UE performs a
TAU. This completes the UE registration in the target EPS and as
part of this the UE may obtain a DCN-ID if the target EPS uses the
DCN-ID. It is open and can be implemented in different ways how an
AMF selects the target MME in case of a UE handover from 5GC to an
EPC supporting DCN.
The handover between 5GC to EPC does not guarantee all active PDU
session(s) of Network Slice(s) can be transferred to the EPC, thus
some PDU session(s) may be dropped. When a UE is ECM-CONNECTED in
EPC, and performs a handover to 5GS, the MME may select the target
AMF based on any available local information (including the UE
Usage Type if one is available for the UE in the subscription data)
and may forward the UE context to the selected AMF over the
MIME-AMF interface. The handover procedure is the executed. When
the Handover is complete, the UE may perform a Registration
procedure. This completes the UE registration in the target 5GS and
as part of this the UE may obtain an Allowed NSSAI. Whether there
is a limitation to the number of Network Slices supported per UE
when interworking with EPS is supported is open and can be
implemented in different ways.
EPC/5GC Interworking
FIG. 2 shows a diagram 200 that illustrates an example of a
non-roaming architecture 200 for interworking between EPC 210 and
5GS 220. Various aspects described herein with respect to a
non-roaming architecture may also apply to a roaming
architecture.
With respect to FIG. 2, the architecture 200 may include a
plurality of interfaces/reference points between modules. The
interfaces may include an MIME-AMF interface 250 which is an
inter-CN interface between the MME 212 and 5GS AMF 222 in order to
enable interworking between EPC 210 and the 5GS 220. As explained
in further detail below, support for the MME-AMF interface 250 in
the network is optional for interworking. In an example, the
MME-AMF interface 250 may support a subset of the functionalities
(essential for interworking) that are supported over reference
points (not shown) between MMEs for MME relocation and MME to MME
information transfer. These reference points can be used intra-PLMN
or inter-PLMN (e.g. in the case of Inter-PLMN HO).
As shown by FIG. 2, the architecture 200 may also include a UDM+HSS
unit 232, a policy control function (PCF)+policy and changing rules
function (PCRF) 234, a SMF+PGW control (PGW-C) 236, and a user
plane function (UPF)+PGW user (PGW-U) 238 dedicated for
interworking between the EPC 210 and the 5GS 220. These units may
be combined entities from the EPC 210 and the 5GS which support
respective functionalities for interworking. However, one or more
of these units (e.g., the PCF+PCRF 234, the SMF+PGW-C 236, and the
UPF+PGW-U 238 may be optional and may be based on capabilities of
one or more of UEs 216, 226 and the architecture 200. One or more
UEs that are not subject to EPC 210 and 5GS 220 interworking may be
served by entities not dedicated for interworking, that is, by one
or more of PGW/PCRF for a UE subject to EPC 210 or SMF/UPF/PCF for
a UE subject to 5GS 220.
In an example, the architecture 200 may also include another UPF
(not shown in FIG. 2) between the NG-RAN 224 and the UPF+PGW-U 238
that is, the UPF+PGW-U 238 can support a reference point with an
additional UPF, if needed. FIG. 2 and the procedures described
herein in connection with FIG. 2 or similar architectures that
depict an SGW 218 make no assumption whether the SGW 218 is
deployed as a monolithic SGW or as an SGW split into its
control-plane and user-plane functionality.
In order to interwork with EPC 210, a UE 216 or 226 that supports
both 5GC 220 and EPC 210 (e.g., supports both 5G or NR as well as
4G technologies) can operate in single-registration mode or
dual-registration mode.
In single-registration mode, a UE may only have one active mobility
management (MM) state (e.g., either RM state in 5GC 220 or EPS
mobility management (EMM) state in EPC 210) and it is either in 5GC
NAS mode or in EPC NAS mode (when connected to 5GC 220 or EPC 210,
respectively). The UE may maintain a single coordinated
registration for 5GC 220 and EPC 210.
In dual-registration mode, the UE can handle independent
registrations for 5GC 220 and EPC 210. In this mode, the UE may be
registered to 5GC 220 only, EPC 210 only, or to both 5GC 220 and
EPC 210.
In an example, support of single registration mode can be mandatory
for UEs that support both 5GC NAS and EPC NAS.
In an example, during a E-UTRAN Initial Attachment procedure, a UE
supporting both 5GC NAS and EPC NAS may need to indicate its
support of 5G NAS in UE Network Capability. For example, during
registration to 5GC 220, the UE supporting both 5GC NAS and EPC NAS
may need to indicate its support of EPC NAS. This indication may be
used to give the priority towards selection of SMF+PGW-C 236 for
UEs that support both EPC NAS and 5GC NAS.
Networks that support interworking with EPC 210, may support
interworking procedures that use the MIME-AMF interface 250 or
interworking procedures that do not use the MME-AMF interface 250.
Interworking procedures with the MME-AMF interface 250 may support
providing IP address continuity on inter-system mobility to UEs
that support 5GC NAS and EPC NAS. Networks that support
interworking procedures without the MME-AMF interface 250 may
support procedures to provide IP address continuity on inter-system
mobility to UEs operating in both single-registration mode and
dual-registration mode.
In some examples, the terms "initial attach," "handover attach,"
and "TAU" for the UE procedures in EPC 210 can alternatively be
combined EPS/International Mobile Subscriber Identity (IMSI) Attach
and/or combined Tracking Area (TA)/Location Area (LA) depending on
the UE configuration.
In an aspect, interworking procedures using the MME-AMF interface
250 may enable the exchange of MM and session management (SM)
states between a source network and a target network. Handover
procedures may support with the MME-AMF interface 250. When
interworking procedures with the MME-AMF interface 250 are used,
the UE may operate in single-registration mode. The network may
retain only one valid MM state for the UE, either in the AMF 222 or
the MME 212. In an example, either the AMF 222 or the MME 212 is
registered in the HSS+UDM 232.
In some examples, support for the MME-AMF interface 250 between AMF
222 in 5GC 220 and the MME 212 in EPC 210 may be needed to enable
seamless session continuity (e.g., for voice services) for
inter-system change.
When the UE supports single-registration mode and the network
supports interworking procedure with the MIME-AMF interface 250:
(a) the UE, for idle-mode mobility from 5GC 220 to EPC 210, may
perform a TAU procedure with EPS GUTI mapped from 5G-GUTI sent as
old Native GUTI. The MME 212 may retrieve the UE's MM and SM
context from 5GC 220 if the UE has a PDU session established or if
the UE or the EPC support "attach without PDN connectivity". The UE
may perform an attach procedure if the UE is registered without PDU
session in 5GC 220 and the UE or the EPC 210 does not support
attach without PDN connectivity. For connected-mode mobility from
5GC 220 to EPC 210, an inter-system handover may be performed.
During the TAU or Attach procedure, the HSS+UDM 232 may cancel any
AMF registration; and (b) the UE, for idle-mode mobility from EPC
210 to 5GC 220, may perform a registration procedure with the EPS
GUTI sent as the old GUTI. The AMF 222 and the SMF+PGW-C 236 may
retrieve the UE's MM and SM context from EPC 210. For
connected-mode mobility from EPC 210 to 5GC 220, inter-system
handover is performed. During the Registration procedure, the
HSS+UDM 232 may cancel any MME registration.
In some examples, interworking may occur without the MME-AMF
interface 250. In this example, IP address continuity may be
provided to the UEs on inter-system mobility by storing and
fetching SMF+PGW-C information and corresponding APN/DDN
information via the HSS+UDM 232. Such networks may also provide an
indication that dual registration mode is supported to UEs during
initial Registration in 5GC. This indication may be valid for the
entire PLMN. UEs that operate in dual-registration mode may use
this indication to decide whether to register early in the target
system. UEs that operate in single-registration mode may use this
indication.
Interworking procedures without the MME-AMF interface 250 may use
the following two items: (1) When PDU sessions are created in 5GC
220, the SMF+PGW-C 236 may update its information along with DNN in
the HSS+UDM 232; or the HSS+UDM 232 may provide the information
about dynamically allocated SMF+PGW-C information and APN/DNN
information to the target CN network.
In some examples, to support mobility for dual-registration mode
UEs, the following additional items may also be supported by the
network: (3) the MME 212, when the UE performs Initial Attach in
EPC 210 and provides an indication that the old node was an AMF
222, may not include "initial attach" indicator to the HSS+UDM 232.
This may result in the HSS+UDM 232 not cancelling the registration
of AMF 222, if any; (4) the AMF 222, when the UE performs Initial
Registration in 5GC 220 and provides the EPS GUTI, may not include
"initial attach" indicator to the HSS+UDM 232. This may result in
the HSS+UDM 232 not cancelling the registration of MME 212, if any;
or (5) the MME 212, when PDN connections are created in EPC 210,
may store the SMF+PGW-C information and APN information in the
HSS+UDM 232.
In some examples, the network may support item 3 above to provide
IP address preservation to UEs operating in single-registration
mode when the UE moves from 5GC 220 to EPC 210. In some examples,
the network may support items 4 and 5, described above, along with
item 6, described below, to provide IP address preservation to UEs
operating in single-registration mode when the UE moves from EPC
210 to 5GC 220. In the following item (6), the AMF 222, when the UE
performs mobility Registration in the 5GC 220 and provides an EPS
GUTI, may determine that the old node is MME 212 and may proceed
with the procedure and provide a "Handover PDU Session Setup with
EPC Supported" indication to the UE in the Registration Accept
message.
In an aspect, mobility may be provided for UEs in
single-registration mode. For example, when the UE supports
single-registration mode and the network supports interworking
procedure without the MIME-AMF interface 250: (a) For mobility from
5GC to EPC, the UE that has received the network indication that
dual registration mode is supported may either: (1) perform Attach
in EPC with Request type "Handover" in PDN CONNECTIVITY Request
message and subsequently moves all its other PDU sessions using the
UE requested PDN connectivity establishment procedure with Request
Type "handover" flag, or (2) perform TAU with 4G-GUTI mapped from
5G-GUTI, in which case the MME 202 may instruct the UE to
re-attach. IP address preservation is not provided in this case. In
an example, the first PDN connection may be established during the
E-UTRAN Initial Attach procedure. In some examples, at inter-PLMN
mobility the UE may use the TAU procedure; or (b) the UE, for
mobility from EPC to 5GC, may perform Registration of type
"mobility registration update" in 5GC with 5G-GUTI mapped from EPS
GUTI. The AMF 204 may determine that old node is an MME 202, but
proceeds as if the Registration is of type "initial registration".
In an example, the Registration Accept includes "Handover PDU
Session Setup Support" indication to the UE. Based on this
indication, the UE may subsequently either: (1) move all PDN
connections of the UE from EPC using the UE initiated PDU session
establishment procedure with "Existing PDU Sessions" flag, or (2)
re-establish PDU sessions corresponding to the PDN connections that
the UE had in EPS. In this case, IP address preservation may not be
provided.
In an aspect, mobility may be provided for UEs in dual-registration
mode. For example, to support mobility in dual-registration mode,
the support of MME-AMF interface 250 between AMF 204 in 5GC and MME
202 in EPC may not be required. Instead, for UE operating in
dual-registration mode the following principles may apply for PDU
session transfer from 5GC to EPC: (a) the UE operating in Dual
Registration mode may register in EPC ahead of any PDU session
transfer using the Attach procedure without establishing a PDN
Connection in EPC if the EPC supports EPS Attach without PDN
Connectivity. In some examples, support for EPS Attach without PDN
Connectivity may be mandatory for a UE supporting dual-registration
procedures. Before attempting early registration in EPC the UE may
need to check whether EPC supports EPS Attach without PDN
Connectivity by reading the related SIB in the target cell; (b) the
UE may perform PDU session transfer from 5GC to EPC using the UE
initiated PDN connection establishment procedure with "handover"
indication in the PDN Connection Request message; (c) if the UE has
not registered with EPC ahead of the PDU session transfer, the UE
can perform Attach in EPC with "handover" indication in the PDN
Connection Request message; (d) the UE may selectively transfer
certain PDU sessions to EPC, while keeping other PDU Sessions in
5GC; (e) the UE may maintain the registration up to date in both
5GC and EPC by re-registering periodically in both systems. In some
examples, if the registration in either 5GC or EPC times out (e.g.
upon mobile reachable timer expiry), the corresponding network may
start an implicit detach timer. In some examples, whether the UE
transfers some or all PDU sessions on the EPC side and whether the
UE maintains the registration up to date in both EPC and 5GC can
depend on UE capabilities that are implementation dependent. In
some examples, the information for determining which PDU sessions
are transferred on EPC side and the triggers can be pre-configured
in the UE.
In an aspect, for a UE operating in dual-registration mode the
following principles may apply for PDN connection transfer from EPC
to 5GC: (a) a UE operating in Dual Registration mode may register
in 5GC ahead of any PDN connection transfer using the Registration
procedure without establishing a PDU session in 5GC; (b) a UE may
perform PDN connection transfer from EPC to 5GC using the UE
initiated PDU session establishment procedure with "Existing PDU
Session" indication; (c) the UE, if the UE has not registered with
5GC ahead of the PDN connection transfer, may perform Registration
in 5GC with "Existing PDU Session" indication in the PDU Session
Request message. In some examples, support of Registration combined
with PDU Session Request may still be open and may be implemented
in different ways; (d) the UE may selectively transfer certain PDN
connections to 5GC, while keeping other PDN Connections in EPC; (e)
the UE may maintain the registration up to date in both EPC and 5GC
by re-registering periodically in both systems. In some examples,
if the registration in either EPC or 5GC times out (e.g. upon
mobile reachable timer expiry), the corresponding network may start
an implicit detach timer. In an example, whether the UE transfers
some or all PDN connections on the 5GC side and whether the UE
maintains the registration up to date in both 5GC and EPC can
depend on UE capabilities that are implementation dependent. In
some examples, the information for determining which PDN
connections are transferred on the 5GC side and the triggers can be
pre-configured in the UE. In an example, if EPC does not support
EPS Attach without PDN Connectivity, the MME 202 may detach the UE
when the last PDN connection is released by the PGW (in relation to
transfer of the last PDN connection to non-3GPP access); or (f) the
network, when sending a control plane request for Mobile
Telecommunication (MT) services (e.g., MT SMS), may route the
control plane via either the EPC or the 5GC. In some examples, in
absence of a UE response, the network may attempt routing the
control plane request via the other system. In an example, the
choice of the system through which the network attempts to deliver
the control plane request first may be determined by network
configuration.
In view of the above descriptions regarding the use of dedicated
core networks (DCNs) in EPC, Network Slicing in 5GC, and EPC/5GC
interworking, the following considerations may be needed.
With the deployment of Network Slicing mechanisms in 5GC networks,
three scenarios need to be considered for the interworking between
5GC and EPC: (1) interworking with EPC not supporting Decor or
eDecor; (2) interworking with EPC supporting Decor; and (3)
interworking with EPC supporting eDecor
Also, considering 5GC/EPC interworking solutions, it is relevant to
consider the following cases: (1) a single-registration UE in a
network supporting an MME-AMF interface; (2) a single-registration
UE in a network supporting dual-registration (without an MME-AMF
interface); and (3) a dual-registration UE in a network supporting
dual-registration.
Deployment of Network Slices in the 5GC may need to be coordinated
by an operator with the DCNs that the operator EPC supports.
Multiple scenarios may need to be considered, for example (a) each
5GC Network Slice may correspond to a specific DCN (i.e., 1:1
mapping); and (b) multiple 5GC Network Slices correspond to a
specific DCN (i.e., N:1 mapping)
In an example, if two Network Slices are "mutually exclusive" in
the 5GC (e.g., the UE can be connected to one slice OR the other),
it may be expected that these two Network Slices correspond to
different DCNs in the EPC.
The issues for these combinations of scenarios can be summarized as
follows: (a) The EPC has no concept of Network Slicing, and does
not understand the information used by the UE and the 5GC for the
support of Network Slicing; (b) if support of multiple Network
Slices has slice co-existence issues (i.e., not all the Network
Slices that the UE has subscribed to can be simultaneously
supported by an AMF, and therefore no serving AMF can support any
combinations of Network Slices for the UE), then specific AMFs may
need to be selected to serve the UE for a subset of the Network
Slices the UE subscribes to. This has been addressed in the
definition of slicing mechanisms by returning to the UE an Allowed
NSSAI, where the network ensures the S-NSSAIs (slices) in the
Allowed NSSAI can co-exist. However, when a UE moves to the EPC
after establishing connectivity to a set of Network Slices in the
5GC, or when the UE first establishes connectivity in the EPC,
either: (1) the EPC, without Decor and eDecor, may not support all
the PDN connections that correspond to the Network Slices the UE
needs to connect to, or (2) in the EPC with Decor or eDecor, no DCN
may exist that supports all the Network Slices the UE needs to
connect to.
This means that either when the UE moves from 5GC to EPC or when a
5GC UE, configured for supporting multiple slicing and mapping
application/services to Network Slices, first establishes
connectivity in the EPC, appropriate connectivity may need to be
provided by the EPC without Decor, or an appropriate DCN may be
selected for the UE. This means: (a) when moving from 5GC to EPC
without Decor, PDU sessions corresponding to the Network Slices for
which the UE has established user plane connectivity in the 5GC may
need to be moved to the EPC. In an example, not all such PDUs may
be supported by the EPC, and some may be dropped/rejected. In an
example, while in the EPC, the UE may activate additional PDN
connections. In some examples, when the UE moves to the 5GC, the
5GC may not have context information mapping the active PDN
connection to the appropriate slices, and therefore the 5GC may not
be capable of: (1) selecting an appropriate serving AMF to support
the required Network Slices, or (2) "distributing" the active PDU
sessions to the Network Slices that the UE needs to be connected
to; and (b) when moving from 5GC to EPC with Decor or eDecor, in
addition to the problem listed above, a correct DCN may need to be
selected to serve the UE. In an example, this may need to be
possible both in case of handover and in case of idle mode
mobility.
The following steps describe problems created by current methods to
resolve the above described issues. In an aspect, "if the UE is in
ECM-IDLE or CM-IDLE state, mobility triggers a TAU (or Attach, if
it is the first mobility event in the target system) in EPS and a
Registration procedure in 5GS. These procedures are sufficient to
place the UE in the right DCN or (set of) Network Slice(s)."
However, this statement is not entirely correct or accurate. In
fact, the following may need to be considered: (a) for idle mode
mobility from EPC to 5GC: In EPC (independently of whether in case
of single radio the UE first registered in 5GC and then moved to
EPC, or first registered in EPC), the UE may have a set of PDN
connections each corresponding to an APN. These PDN connections may
correspond to PDU sessions transferred from the 5GC, or established
directly in the EPC, or a combination of both. If operators use
generic APNs, or non-slice specific/dedicated APNs, for
connectivity to specific slices, and have corresponding APNs for
the use over EPC, then (1) in case of a single-registration UE and
no MIME-AMF interface, when the UE performs a Registration in the
5GC the UE can provide the needed Requested NSSAI thus the correct
AMF and set of slices can be selected; (2) in case of dual
registration, when the UE performs a Registration in the 5GC, the
UE can provide the needed Requested NSSAI thus the correct AMF and
set of slices can be selected; or (3) however, in case of a
single-registration UE and MME-AMF interface, when the UE performs
a Registration in the 5GC and the context is retrieved from the
MME, the AMF may only receive a context containing the PDU sessions
and the corresponding APNs, but may not receive any slicing
information that would identify the Network Slices the UE needs to
be connected to (in order to support the active PDU sessions), or
the mapping between the PDU sessions and any slices.
In another aspect, "when a UE CM state in the AMF is CM-CONNECTED
in 5GC and a handover to EPS occur, the AMF selects the target MME
and forwards the UE context to the selected MME over the MME-AMF
Interface." The EPC can select the AMF only based on the location
of the target 5G-RAN node, without any considerations of slicing:
this implies that the AMF that is selected as a "generic AMF" that
must be capable of supporting simultaneously all the PDU sessions
corresponding potentially to different slices in order to enable
the mobility. Once the UE performs the Registration procedure at
the end of the handover, the UE can provide the actual Requested
NSSAI, and an AMF relocation may need to happen. However, the 5GC
must deploy such "generic AMFs" to enable the handover.
In another aspect, "when a UE is ECM-CONNECTED in EPC, and performs
a handover to 5GS . . . . When the Handover completes the UE
performs a Registration procedure. This completes the UE
registration in the target 5GS and as part of this the UE obtains
an Allowed NSSAI." In the case where multiple 5GC slices correspond
to a specific DCN, when the UE is connected to the EPC to a given
DCN with one or more active PDN connections, unless explicit
information is provided at a certain time to the 5GC in the
mobility from EPC to 5GC, the 5GC may have no way to know to which
slice a given PDU session correspond. This may be particularly true
if a given APN can apply to multiple S-NSSAIs (i.e. non-slice
specific APNs).
In another aspect, "UE operating in Dual Registration mode may
register in EPC ahead of any PDU session transfer using the Attach
procedure without establishing a PDN Connection in EPC if the EPC
supports EPS Attach without PDN Connectivity." In this scenario,
sufficient information may not exist to correctly select the DCN
for the UE in such a way to enable correct interworking with the
slices to which the UE is connected over the 5GC. Specifically,
based on EPC mechanisms: (a) when Decor is supported, the MME/DCN
may be selected solely based on EPC subscription information. In
order to ensure that the correct DCN is selected, a UE Usage Type
that can map to any combination of slices that the UE may have
requested over 5GS is required, which may not be realistic in all
cases. Also, this may require that a DCN exists that supports any
combination of slices. If this is not the case, then when the UE
moves PDU sessions to the EPC, the PDU sessions will be dropped
even if an appropriate DCN existed in the EPC, simply because the
selected DCN was based solely on subscription information; (b) when
eDecor is supported, a DCN ID mapping to the set (or a subset) of
slices that the UE has connectivity to over the 5GS may need to be
provided by the UE, if it is possible for such a value to exist; or
(c) the same may apply to the statement "if the UE has not
registered with EPC ahead of the PDU session transfer, the UE can
perform Attach in EPC with "handover" indication in the PDN
Connection Request message."
In another aspect, "UE operating in Dual Registration mode may
register in 5GC ahead of any PDN connection transfer using the
Registration procedure without establishing a PDU session in 5GC.
The UE performs PDN connection transfer from EPC to 5GC using the
UE initiated PDU session establishment procedure with "Existing PDU
Session" indication." If eDECOR is not used but the network
supports DCNs, the UE may have no awareness of the DCN selected for
the UE. In order to move the established PDN connection to the
correct slices, based on the Requested NSSAI the UE provides at the
Registration procedure in the 5GC: (a) there may need to be a
correspondence between the DCN selected in EPC and the set of
slices on the 5GC. At a minimum, the correct PGW/SMF node may need
to have been selected if PDN connections were established in the
EPC, to ensure that the PGW/SMF is part of the appropriate slice;
or (b) there may need to be a correspondence between the APN used
over the EPC for the PDN connections and the "APN+S-NSSAI"
combination used for a PDU session in the 5GC; or (c) The same may
apply to the text stating that "if the UE has not registered with
5GC ahead of the PDN connection transfer, the UE can perform
Registration in 5GC with "Existing PDU Session" indication in the
PDU Session Request message."
In another aspect, when a UE performs an attach or TAU in EPC and
no DCN information is available, the MME may be selected by the RAN
according to other factors. If this corresponds to a scenario in
which a single registration UE is performing idle mode mobility
from the 5GC to the EPC, the MME selected may not belong to the
correct DCN to serve the UE based on the active PDN sessions and
corresponding slices in the 5GC. According to mechanisms currently
standardized for DCNs in EPC: (a) if the MME does not have
sufficient information to determine whether it cans serve the UE,
the MME may send an Authentication Information Request message to
the HSS requesting UE Usage Type. The HSS, if supporting DCNs, may
provide the UE Usage Type in the Authentication Information Answer
message. The MME can therefore decide whether it can serve the UE
or whether an MME in a different DCN needs to be selected. However,
the UE Usage Type stored in the HSS is a semi-static configuration
parameter that may not match the set of slices active for the UE in
the 5GC. This is particularly true for devices that subscribe to a
variety of slices, including slices that cannot co-exist; or (b) in
case of idle mode mobility or a UE between MMEs, or idle-mode
mobility of a single-registration UE between an AMF and the MME,
the target MME receives the MM and SM context from the target node
after the UE triggers the MM procedure (e.g. TAU) and the RAN
selects the MME. However, in such scenarios no mechanisms are
defined for the selected MME to determine whether it can serve the
UE or whether redirection to another MME based on the MM/SM context
is required.
Various solutions are described below that provide techniques or
mechanism to enable interworking between 5GS network slicing and
EPC connectivity. These solutions involve one or more of the
following aspects: (a) enhance NSSP policies to map not only
applications to slices (i.e. the S-NSSAI) and to the DNN, but also
to the APN to be used when the UE is in the EPC; (b) enhance the UE
functionality to maintain the mapping between active PDN
connections and the corresponding S-NSSAI when the UE moves to the
EPC or when new PDN connections are created while the UE is in the
EPC. The UE may use such information when moving from EPC to 5GC
and will provide it to the AMF during an RM procedure (e.g.,
Registration procedure); (c) enhance the AMF to be configured with
a mapping between a set of S-NSSAIs in the Allowed S-NSSAI assigned
to a UE to a DCN in the EPC; (d) enhance SMF/PGW-C selection
functionality to ensure that the AMF selects an SMF considering the
mapping between the S-NSSAIs in the Allowed NSSAI and DCNs in the
EPC to ensure that the selected SMF/PGW-C is part of the mapped DCN
from the Allowed NSSAI; or (e) ensure the UE Usage Type maintained
in the HSS is augmented with a Temporary UE Usage Type set by the
AMF based on the Allowed NSSAI, and pushed to the HSS when an
Allowed NSSAI is allocated to the UE. When an MME asks the UE Usage
Type from the HSS, if the Temporary UE Usage Type is set, the HSS
provides such value. In this way the MME can select the DCN serving
the UE based on dynamic information and not just subscription
information.
In more details, the solutions described above involve one or more
mechanisms. In one aspect, (1) UE-maintained connections may be
mapped to slicing information. In an example, when connecting to a
5GC with network slicing, the UE may use the configured NSSP to
select the S-NSSAI (and DNN) to be used for an application. In
combination with the Configured NSSAI, this may enable the UE to
construct the needed Requested NSSAI to support
services/applications in the UE. In order to enable interworking
with EPC, the UE may maintain a mapping, for each active PDU
session, of the <DNN, S-NSSAI> to a PDU Session ID for each
active PDU session. In some examples, the UE may receive the
corresponding NSSAI in a Protocol Configuration Option (PCO) field
in response to a new PDN connection being created while the UE is
in the EPC.
In some examples, for each <DNN, S-NSSAI> mapping for an
application/service, the NSSP may also contain the mapping to an
APN to be used by the UE when connected to the EPC (that is, when
the UE establishes a PDN connection while connected to the EPC
either with the 3GPP access connected to the EPC or via non-3GPP
access (e.g. via untrusted non-3GPP and an ePDG)), if the APN used
in the EPC is different from the DNN used in the 5GC. In this way,
a single mapping of applications and connectivity may exist in the
UE.
In some examples, when the UE first establishes PDU sessions via
the 5GC and then moves the PDU sessions to the EPC, for the PDU
sessions that are moved to the EPC (a selective set in case of
dual-registration UE, or the set of PDU sessions that are supported
in EPC after the mobility to EPC), the UE may maintain for each PDN
connection the mapping between the <DNN, S-NSSAI> and the PDU
Session ID that would apply for this PDU session in the 5GC, and to
the APN corresponding to the PDN connection in the EPC. This may be
particularly important for PDN connections established while the UE
is connected to the EPC.
In some examples, when the UE moves from the EPC to the 5GC (e.g.,
for single registration UE this applies to idle mode mobility and
to MME-AMF interface handover; for dual-radio UE this applies to
the registration performed in the 5GC when the UE is connected to
the EPC, either ahead of the UE moving the PDN connections, or when
the UE triggers the mobility of the first PDN connection to the
5GS), the UE may provide the mapping of S-NSSAIs to PDU session
IDs, and possibly the mapping of PDU session IDs to the related
DNN, to the 5GC in NAS mobility management messages (e.g.
Registration Request) in addition to the Requested NSSAI. This may
enable the AMF receiving such information to identify which Network
Slices correspond to the PDN connections that were active for the
UE in the EPC.
In another aspect, (2) as an alternative to (1) above, when the UE
moves from the 5GC to the EPC, the UE may provide to the MME in NAS
MM procedures (e.g. TAU) a "Slicing Information Container" that may
contain a mapping between the PDU sessions and the corresponding
slices (that is, mapping of PDU Session ID to S-NSSAI). The MME may
not interpret such information but may store it. In some examples,
the UE may update the information in the MME each time a PDN
connection is added or dropped (including if the handover of PDU
sessions from the 5GC to the EPC results in some PDU sessions being
dropped). In some examples, in case of handover from the EPC to the
5GC, or when the AMF retrieves the context from the MME in idle
mode mobility, the MME may provide the stored container to the AMF.
The AMF may use the information in the container to map the PDU
sessions to the appropriate slices (i.e. S-NSSAI).
In another aspect, (3) in addition to the previous solutions, for
scenarios where a single-registration UE connects first to the 5GC,
then moves to the EPC, and returns to the 5GC, instead of providing
in RRC signaling the 5G GUTI previously allocated by the AMF, the
UE may provide only the Requested NSSAI based on the set of slices
required by the UE, in order to enable the RAN to select an AMF
that can serve the set of slices to which the UE connects to. The
UE may provide however the 5G GUTI in NAS signaling.
In yet another aspect, (4) a UE that has registered with an AMF
indicating the ability to connect to the EPC, when an SMF is
selected during PDU session creation (e.g. by the AMF or NSSF or
NRF), the entity selecting the SMF may consider the mapping between
the S-NSSAIs and DCNs in the SMF selection. The consideration of
the mapping may be done to enable the selection of an SMF/PGW-C
that is in the correct DCN, in order to support mobility to the
EPC. For example, if S-NSSAI1 would map to DCN1 and S-NSSAI2 would
map to DCN2, when an SMF is selected for a PDU session
corresponding to S-NSSAI1, an SMF/PGW combo for S-NSSAI1 that
belongs to DCN1 may need to be selected.
In yet another aspect, (5) when an MME receives an attach or TAU
from a UE that is previously registered with a core network node
(e.g., AMF) identified by the UE temporary identifier provided by
the UE (e.g. the mapped GUTI a single-registration UE provides to
the MME, creating it from the 5G GUTI the UE obtained in the 5GC
from an AMF), the MME may retrieve the MM/SM context from the
source core network node (e.g. the AMF) and may determine, based on
the received MM/SM context, whether the MME can serve the UE or
whether redirection to an MME in another DCN is required. The MME
may perform the determination based on the content of the MM/SM
context. To enable this, the AMF may receive from the HSS/UDM both
the 5G and the EPC subscription information, and mapping
information between the DNN used in the 5G system and the APNs to
be used in the EPC. The AMF, when providing the SM context to the
MME, may provide the PDU session IDs of PDU sessions and the APN
that corresponds to the DNN of the PDU session.
In yet another aspect, (6) an alternative to (5), for each
subscriber of a network deploying both EPC and 5GC, the common
HSS/UDM node may store a UE Usage Type. The HSS may also store a
Current UE Usage Type value, which is set by an AMF.
In some examples, the AMF may be configured with mapping
information to map combinations of S-NSSAIs to Usage Type
values.
In some examples, when the AMF allocates an Allowed NSSAI to the
UE, the AMF may also send the mapped UE Usage Type to the HSS, and
the HSS may store the mapped UE Usage Type as the Current UE Usage
Type.
In some examples, when an MME retrieves from the UE the UE Usage
Type, if the HSS has a stored Current UE Usage Type, the HSS may
provide to the UE the Current UE Usage Type. This may help an MME
to determine if the MME can serve a UE when a UE performs an attach
or TAU procedure with the MME after having established a context
with the AMF. In this way, the MME can select a serving MME
corresponding to the DCN that supports the slices that the UE is
connected to over the 5GC.
In some examples, optionally, when the HSS receives a new value of
the Temporary UE Usage Type and determines that the UE has a
registration to the 5GC and a registration to the EPC, the HSS may
trigger a UE Usage Type update to the MME. Upon receiving such
update, the MME may store the received UE Usage Type and may
remember that the UE Usage Type was modified. Upon the UE
performing signalling towards the MME, the MME may determine
whether the MME can serve the UE based on the received UE usage
type and, if not, the MME triggers an MME re-allocation to a new
serving MME.
Referring to FIG. 3, there is shown a flow diagram of an example of
a method 300 according to the above-described aspects for
interworking between 5GS network slicing and EPC connectivity, the
method 300 including one or more of the herein-defined actions.
For example, at 302, the method 300 may include enabling NSSPs to
map applications to network slices, to a DNN, and to an APN to be
used when a UE is in the EPC. As an example, when the APN used in
the EPC is different from the DNN used in the 5GS. For instance, in
an aspect, one or more of the devices described herein may execute
the actions in 302.
At 304, the method 300 includes mapping the applications. For
instance, in an aspect, one or more of the devices described herein
may execute the actions in 304.
At 306, the method 300 optionally includes maintaining a mapping of
the network slices, the DNN, and the APN to a packet data unit
(PDU) session identity (ID) for each active PDU session. For
instance, in an aspect, one or more of the devices described herein
may execute the actions in 306.
Referring to FIG. 4, there is shown is a flow diagram of an example
of a method 400 according to the above-described aspects for
interworking between 5GS network slicing and EPC connectivity, the
method 400 including one or more of the herein-defined actions.
For example, at 402, the method 400 includes enabling UE
functionality to maintain a mapping between active PDN connections
and a corresponding S-NSSAI in response to the UE moving to an EPC
or in response to new PDN connections are created while the UE is
in the EPC. For instance, in an aspect, one or more of the devices
described herein may execute the actions in 402. As used herein,
the terms PDN connection and PDU session are equivalent and can be
used interchangeably.
At 404, the method 400 includes providing information about the
mapping to an AMF during a registration procedure. For instance, in
an aspect, one or more of the devices described herein may execute
the actions in 404.
Referring to FIG. 5, there is shown is a flow diagram of an example
of a method 500 according to the above-described aspects for
interworking between 5GS network slicing and EPC connectivity, the
method 500 including one or more of the herein-defined actions.
For example, at 502, the method 500 includes enabling an AMF
supporting a connectivity to a variety of network slices to be
configured with a mapping between a set of network slices (e.g.,
each can be identified by an S-NSSAIs) in a list of network slices
allowed by the network for the UE (that is, in an allowed S-NSSAI
assigned to a UE) to a specific DCN in an EPC. For instance, in an
aspect, one or more of the devices described herein may execute the
actions in 502. As described herein, a network slice is a slice
identified by S-NSSAI, an allowed network slice is a slice
identified by allowed NSSAI, and similarly for other network
slices.
At 504, the method 500 includes applying the mapping. For instance,
in an aspect, one or more of the devices described herein may
execute the actions in 504.
Referring to FIG. 6, there is shown is a flow diagram of an example
of a method 600 according to the above-described aspects for
interworking between 5GS network slicing and EPC connectivity, the
method 600 including one or more of the herein-defined actions.
For example, at 602, the method 600 includes enabling an
SMF-selection functionality to ensure that an AMF selects an SW for
establishing a PDU session for a UC corresponding to a network
slice (e.g., identified by S-NSSAI) considering a mapping between a
set of network slices (e.g., identified by an S-NSSAIs) and DCNs in
the EPC, in order to ensure the SMF may continue supporting the
connectivity management for the PDU session when the UE moves the
PDU session to the EPC and a specific DCN is select to serve the UE
based on the mapping between the network slices and the DCNs. For
instance, in an aspect, one or more of the devices described herein
may execute the actions in 602.
At 604, the method 600 includes applying the SMF-selection
functionality. For instance, in an aspect, one or more of the
devices described herein may execute the actions in 604.
Referring to FIG. 7, there is shown is a flow diagram of an example
of a method 700 according to the above-described aspects for
interworking between 5GS network slicing and EPC connectivity, the
method 700 including one or more of the herein-defined actions.
For example, at 702, the method 700 includes augmenting a
subscribed UE usage type maintained in an HSS with a temporary UE
usage type set by an AMF based on an allowed S-NSSAI. For instance,
in an aspect, one or more of the devices described herein may
execute the actions in 702.
At 704, the method 700 includes providing the temporary UE usage
type to the HSS when the allowed S-NSSAI is allocated to the UE.
For instance, in an aspect, one or more of the devices described
herein may execute the actions in 704.
At 706, the method 700 optionally includes storing, in the HSS, the
temporary UE usage type in addition to the subscribed UE usage
type.
At 708, the method 700 optionally includes when providing the UE
usages type to an MME, if the HSS has a stored temporary UE usage
type, the HSS provided the temporary UE usage type.
Referring to FIG. 8, one example of an implementation of UE 110 may
include a variety of components, some of which have already been
described above, but including components such as one or more
processors 812 and memory 816 and transceiver 802 in communication
via one or more buses 844, which may operate in conjunction with
modem 140 and the interworking component 150 to enable one or more
of the functions described herein related to mechanisms that enable
interworking between 5GS network slicing and EPC connectivity.
Further, the one or more processors 812, modem 140, memory 816,
transceiver 802, RF front end 888 and one or more antennas 865, may
be configured to support voice and/or data calls (simultaneously or
non-simultaneously) in one or more radio access technologies.
In an aspect, the one or more processors 812 can include the modem
140 that uses one or more modem processors. The various functions
related to interworking component 150 may be included in modem 140
and/or processors 812 and, in an aspect, can be executed by a
single processor, while in other aspects, different ones of the
functions may be executed by a combination of two or more different
processors. For example, in an aspect, the one or more processors
812 may include any one or any combination of a modem processor, or
a baseband processor, or a digital signal processor, or a transmit
processor, or a receiver processor, or a transceiver processor
associated with transceiver 802. In other aspects, some of the
features of the one or more processors 812 and/or modem 140
associated with interworking component 150 may be performed by
transceiver 802.
Also, memory 816 may be configured to store data used herein and/or
local versions of applications 875 or interworking component 150
and/or one or more of its subcomponents being executed by at least
one processor 812. Memory 816 can include any type of
computer-readable medium usable by a computer or at least one
processor 812, such as random access memory (RAM), read only memory
(ROM), tapes, magnetic discs, optical discs, volatile memory,
non-volatile memory, and any combination thereof. In an aspect, for
example, memory 816 may be a non-transitory computer-readable
storage medium that stores one or more computer-executable codes
defining interworking component 150 and/or one or more of its
subcomponents, and/or data associated therewith, when UE 110 is
operating at least one processor 812 to execute interworking
component 150 and/or one or more of its subcomponents. The
interworking component 150 may include one or more subcomponents
configured to perform at least some of the actions described above
in connection with methods 300, 400, 500, 600, and/or 700.
Transceiver 802 may include at least one receiver 806 and at least
one transmitter 808. Receiver 806 may include hardware, firmware,
and/or software code executable by a processor for receiving data,
the code comprising instructions and being stored in a memory
(e.g., computer-readable medium). Receiver 806 may be, for example,
a radio frequency (RF) receiver. In an aspect, receiver 806 may
receive signals transmitted by at least one base station 125.
Additionally, receiver 806 may process such received signals, and
also may obtain measurements of the signals, such as, but not
limited to, Ec/Io, SNR, RSRP, RSSI, etc. Transmitter 808 may
include hardware, firmware, and/or software code executable by a
processor for transmitting data, the code comprising instructions
and being stored in a memory (e.g., computer-readable medium). A
suitable example of transmitter 808 may including, but is not
limited to, an RF transmitter.
Moreover, in an aspect, UE 110 may include RF front end 888, which
may operate in communication with one or more antennas 865 and
transceiver 802 for receiving and transmitting radio transmissions,
for example, wireless communications transmitted by at least one
base station 125 or wireless transmissions transmitted by UE 110.
RF front end 888 may be connected to one or more antennas 865 and
can include one or more low-noise amplifiers (LNAs) 890, one or
more switches 892, one or more power amplifiers (PAs) 898, and one
or more filters 896 for transmitting and receiving RF signals.
In an aspect, LNA 890 can amplify a received signal at a desired
output level. In an aspect, each LNA 890 may have a specified
minimum and maximum gain values. In an aspect, RF front end 888 may
use one or more switches 892 to select a particular LNA 890 and its
specified gain value based on a desired gain value for a particular
application.
Further, for example, one or more PA(s) 898 may be used by RF front
end 888 to amplify a signal for an RF output at a desired output
power level. In an aspect, each PA 898 may have specified minimum
and maximum gain values. In an aspect, RF front end 888 may use one
or more switches 892 to select a particular PA 898 and its
specified gain value based on a desired gain value for a particular
application.
Also, for example, one or more filters 896 can be used by RF front
end 888 to filter a received signal to obtain an input RF signal.
Similarly, in an aspect, for example, a respective filter 896 can
be used to filter an output from a respective PA 898 to produce an
output signal for transmission. In an aspect, each filter 896 can
be connected to a specific LNA 890 and/or PA 898. In an aspect, RF
front end 888 can use one or more switches 892 to select a transmit
or receive path using a specified filter 896, LNA 890, and/or PA
898, based on a configuration as specified by transceiver 802
and/or processor 812.
As such, transceiver 802 may be configured to transmit and receive
wireless signals through one or more antennas 865 via RF front end
888. In an aspect, transceiver may be tuned to operate at specified
frequencies such that UE 110 can communicate with, for example, one
or more base stations 125 or one or more cells associated with one
or more base stations 125. In an aspect, for example, modem 140 can
configure transceiver 802 to operate at a specified frequency and
power level based on the UE configuration of the UE 110 and the
communication protocol used by modem 140.
In an aspect, modem 140 can be a multiband-multimode modem, which
can process digital data and communicate with transceiver 802 such
that the digital data is sent and received using transceiver 802.
In an aspect, modem 140 can be multiband and be configured to
support multiple frequency bands for a specific communications
protocol. In an aspect, modem 140 can be multimode and be
configured to support multiple operating networks and
communications protocols. In an aspect, modem 140 can control one
or more components of UE 110 (e.g., RF front end 888, transceiver
802) to enable transmission and/or reception of signals from the
network based on a specified modem configuration. In an aspect, the
modem configuration can be based on the mode of the modem and the
frequency band in use. In another aspect, the modem configuration
can be based on UE configuration information associated with UE 110
as provided by the network during cell selection and/or cell
reselection.
Referring to FIG. 9, one example of an implementation of a network
device 900 may include a variety of components, some of which have
already been described above, but including components such as one
or more processors 912 and memory 916 and transceiver 902 in
communication via one or more buses 944, which may operate in
conjunction with an interworking component 950 to enable one or
more of the functions described herein related to network-side
operations associated with mechanisms that enable interworking
between 5GS network slicing and EPC connectivity. In an example,
the network device 900 can implement at least some of the
functionality of an AMF or an MME (see FIG. 2), where such
functionality is related to network-side operations associated with
mechanisms that enable interworking between 5GS network slicing and
EPC connectivity
The transceiver 902, receiver 906, transmitter 908, one or more
processors 912, memory 916, applications 975, and buses 944 may be
the same as or similar to the corresponding components of UE 110,
as described above, but configured or otherwise programmed for
network-side operations as opposed to UE operations. The
transceiver 902 may be configured to support an interface such as,
for example, the MME-AMF interface described above in connection
with FIG. 2.
The above detailed description set forth above in connection with
the appended drawings describes examples and does not represent the
only examples that may be implemented or that are within the scope
of the claims. The term "example," when used in this description,
means "serving as an example, instance, or illustration," and not
"preferred" or "advantageous over other examples." The detailed
description includes specific details for the purpose of providing
an understanding of the described techniques. These techniques,
however, may be practiced without these specific details. In some
instances, well-known structures and apparatuses are shown in block
diagram form in order to avoid obscuring the concepts of the
described examples.
Information and signals may be represented using any of a variety
of different technologies and techniques. For example, data,
instructions, commands, information, signals, bits, symbols, and
chips that may be referenced throughout the above description may
be represented by voltages, currents, electromagnetic waves,
magnetic fields or particles, optical fields or particles,
computer-executable code or instructions stored on a
computer-readable medium, or any combination thereof.
The various illustrative blocks and components described in
connection with the disclosure herein may be implemented or
performed with a specially-programmed device, such as but not
limited to a processor, a digital signal processor (DSP), an ASIC,
a FPGA or other programmable logic device, a discrete gate or
transistor logic, a discrete hardware component, or any combination
thereof designed to perform the functions described herein. A
specially-programmed processor may be a microprocessor, but in the
alternative, the processor may be any conventional processor,
controller, microcontroller, or state machine. A
specially-programmed processor may also be implemented as a
combination of computing devices, e.g., a combination of a DSP and
a microprocessor, multiple microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration.
The functions described herein may be implemented in hardware,
software executed by a processor, firmware, or any combination
thereof. If implemented in software executed by a processor, the
functions may be stored on or transmitted over as one or more
instructions or code on a non-transitory computer-readable medium.
Other examples and implementations are within the scope and spirit
of the disclosure and appended claims. For example, due to the
nature of software, functions described above can be implemented
using software executed by a specially programmed processor,
hardware, firmware, hardwiring, or combinations of any of these.
Features implementing functions may also be physically located at
various positions, including being distributed such that portions
of functions are implemented at different physical locations. Also,
as used herein, including in the claims, "or" as used in a list of
items prefaced by "at least one of" indicates a disjunctive list
such that, for example, a list of "at least one of A, B, or C"
means A or B or C or AB or AC or BC or ABC (i.e., A and B and
C).
Computer-readable media includes both computer storage media and
communication media including any medium that facilitates transfer
of a computer program from one place to another. A storage medium
may be any available medium that can be accessed by a general
purpose or special purpose computer. By way of example, and not
limitation, computer-readable media can comprise RAM, ROM, EEPROM,
CD-ROM or other optical disk storage, magnetic disk storage or
other magnetic storage devices, or any other medium that can be
used to carry or store desired program code means in the form of
instructions or data structures and that can be accessed by a
general-purpose or special-purpose computer, or a general-purpose
or special-purpose processor. Also, any connection is properly
termed a computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of medium. Disk and disc,
as used herein, include compact disc (CD), laser disc, optical
disc, digital versatile disc (DVD), floppy disk and Blu-ray disc
where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above are
also included within the scope of computer-readable media.
The previous description of the disclosure is provided to enable a
person skilled in the art to make or use the disclosure. Various
modifications to the disclosure will be readily apparent to those
skilled in the art, and the common principles defined herein may be
applied to other variations without departing from the spirit or
scope of the disclosure. Furthermore, although elements of the
described aspects and/or embodiments may be described or claimed in
the singular, the plural is contemplated unless limitation to the
singular is explicitly stated. Additionally, all or a portion of
any aspect and/or embodiment may be utilized with all or a portion
of any other aspect and/or embodiment, unless stated otherwise.
Thus, the disclosure is not to be limited to the examples and
designs described herein but is to be accorded the widest scope
consistent with the principles and novel features disclosed
herein.
* * * * *
References